The government yesterday mounted the most detailed defence to date of its decarbonisation record, in the face of on-going protests from Extinction Rebellion (XR) and accusations from School Strikes founder Greta Thunberg that political leaders have lied to the younger generation.

In another hugely eventful day for the UK climate movement, Thunberg visited Parliament to meet with Party leaders and deliver a stinging address to an audience of MPs and officials accusing the older generation of betraying the promise of a better future that they had made to young people.

"We probably don't even have a future any more," she said. "Because that future was sold so that a small number of people could make unimaginable amounts of money. It was stolen from us every time you said that the sky was the limit, and that you only live once. You lied to us. You gave us false hope. You told us that the future was something to look forward to. And the saddest thing is that most children are not even aware of the fate that awaits us."

She also aimed specific criticism at the UK government, highlighting its "mind-blowing historical carbon debt", describing new investment in high carbon infrastructure such as fracking projects and Heathrow expansion as "beyond absurd", and accusing Ministers of "creative" carbon accounting that failed to take proper account of shipping, aviation, and imported emissions.

The speech prompted a standing ovation and a chastened response from those political leaders who shared a platform with Thunberg.

Environment Secretary Michael Gove said Thunberg's voice was "like the voice of our conscience". "When I listened to you, I felt great admiration, but also responsibility and guilt," he said. "I am of your parents' generation, and I recognise that we haven't done nearly enough to address climate change and the broader environmental crisis that we helped to create."

Former Labour leader Ed Miliband similarly thanked Thunberg for having "woken us up". "All the young people who have gone on strike have held up a mirror to our society… you have taught us all a really important lesson," he said. "You have stood out from the crowd."

Later in the day Miliband secured an Urgent Question in the House of Commons on the government's response to the XR protests and wider climate strategy.

The debate prompted a flurry of criticism of the government's record, highlighting recent confirmation the UK is still on track to miss its medium term carbon targets, the relative paucity of climate adaptation programmes, the axing of a raft of decarbonisation policies in recent years, and the failure to come forward with new policies to help close the 'emissions gap'.

However, energy and clean growth minister Claire Perry responded with the most detailed defence of the government's record since the XR protests started over a week ago, insisting that the highlighting of the UK's successful climate policies was not evidence of complacency but a strategic choice designed to help build as much support as possible for the next phase of decarbonisation.

Perry praised the protestors for demonstrations that have "by and large been good-natured" and the police for a response that has been "sensible and proportionate". And she welcomed the "strong and growing pressure for more action to cut our emissions". "It has been incredibly powerful to see people of all generations across the world voicing their concerns about a warming climate and demanding a global response to this global crisis," she said.

However, she also insisted the government was right to highlight the progress the UK has made in cutting emissions 42 per cent since 1990 while growing the economy by 72 per cent.

"We should… ensure that while we acknowledge the scale of the challenge ahead, we do try as hard as we can to build a consensus around change so that communities across the UK and indeed across the world feel secure, feel optimistic and feel involved in our shifts to decarbonise the economy," she argued. "I think we should be talking about hope, not fear and communicating the progress that we have made globally and have made here in the UK which does demonstrate that this urgent action to decarbonise our economy can sit comfortably alongside opportunity, growth and employment going forward."

She insisted that such rhetoric should not be mistaken for complacency. "We entirely accept that concerted and more action at national and international level is urgently required," she added. "[But] I still feel we must focus on the fact [the UK has made significant progress cutting emissions], because it shows it is possible, that we have shown real leadership in the UK thanks to the cross-party consensus we have forged on this since the passage of our world-leading Climate Change Act over a decade ago."

Perry also issued a plea for the cross party consensus on climate change to be maintained as the debate on how to decarbonise becomes more heated, expressing her "fervent hope" that Parliament will continue to tackle this "enormous crisis" in a spirit of cross-party co-operation going forward.

And she defended the government's carbon accounting methods, insisting that even when imported or consumption-based emissions are taken into account official figures show UK greenhouse gas emissions on a consumption basis fell 21 per cent between 2007 and 2016 and dropped six per cent year on year in the year to 2016.

In addition, Perry rejected accusations the government had soft-pedalled on climate policies in recent years.

She acknowledged "colleagues will be sick of me waving the Clean Growth Strategy around", but insisted the November 2017 strategy was "one of the most comprehensive documents any government has put out across the world detailing how we will take decarbonisation action across the economy" and was supporting low carbon industries that are already bigger than the aerospace sector and are growing at a factor of two or three times the mainstream economy.

She also highlighted the UK's leadership of the international Powering Past Coal Alliance, the recent launch of the Offshore Wind Sector Deal, the Chancellor's announcement last month of a new Future Homes Standard and Green Gas initiative, the running of the UK grid without coal power throughout the Easter Weekend, and Defra's 25 Year Environment Plan and new Resources and Waste Strategy.

Perry provided one new announcement, confirming the second annual Green Great Britain Week will take place the week of November 4 this year. "We look forward to the celebrations and also the challenges around that," she said, perhaps acknowledging that the Week could face further action from protestors.

She argued the UK should celebrate progress to date, "not in order to imply we are in any way complacent and not to suggest we don't need to go very much more rapidly and further, but to demonstrate that this is a win-win both for the planet and for future generations in terms of their jobs and prosperity".

She concluded by highlighting the imminent release of the Committee on Climate Change's advice on whether the UK should set a new net zero emission target and promising to "engage colleagues across this House on next steps in the light of this".

And she urged XR to be mindful of the need to build as wide as coalition as possible in pursuit of a rapid, economy-wide low carbon transition.

"I welcome the passion and fervour of the protesters, and their constant reminder to us of the duties we face in raising our eyes for the next few years of the conversation about our relationship with Europe and thinking about the long-term challenges that we face," she said. "I hope those who have taken their passion public will continue to express their views without disrupting the daily lives of ordinary people, and without endangering the safety of the public. And also without undermining the consensus we will need to support further, bolder action.

"We must work together to solve this challenge of climate change - in this House, in the other place, in classrooms across the UK, in boardrooms across the UK, in international negotiating huddles, in homes and through civil society - to deliver the broad, just and progressive action on climate change that we urgently need."

The latest developments came amid evidence the XR protests are helping to widen the coalition in support of bolder climate action. 

Yesterday Oxford City Council announced it is to launch the UK's first Citizens Assembly to address the 'climate emergency', while a new Sky Data poll revealed significant support for XR's aims, if not its tactics.

The survey of 1,000 people found 53 per cent oppose the disruptive tactics employed by the climate change activists, while just 29per cent approve of them.

But 60 per cent saif they approved of XR's aims, while just 20per cent diaspproved, and 31 per cent said they had been inspired to do more to tackle climate change, in contrast to 26 per cent who said they have been put off by the protests.

Perry's plea for a greater appreciation of the UK's decarbonisation record is likely to gain limited traction, as XR continues to plot a further wave of protests for this week.

Political opponents were quick to point out that the government is still yet to come forward with new policies to put it on track to meet its medium term carbon targets and has repeatedly failed to address accusations that support for new high carbon infrastructure is incompatible with efforts to cut emissions as quickly as possible.

Moreover, Perry's plea for the continuation of the cross-party consensus on climate action was undermined yesterday by Prime Minister Theresa May's failure to join other Westminster Party leaders in meeting Thunberg.

The Greens Caroline Lucas, Labour's Jeremy Corbyn, the SNP's Ian Blackford, the Lib Dem's Vince Cable, and Plaid Cymru's Liz Saville-Roberts all met Thunberg and representatives of the UK School Strikes network and issued a joint statement promising on-going co-operation to tackle the climate crisis.

Specifically the group committed to ongoing cross-party roundtables with the youth climate strikers and increased cross-party collaboration on climate change, including an agreement to issue a statement endorsing the UK's bid to host COP26 in 2020; actively support and engage with youth climate assemblies in towns and cities across the UK; and accept, as a minimum, the CCC's recommendations on a new net zero emission goal.

Significantly, they also agreed to "seek a common framework to ensure party policy and manifestos are in line with CCC recommendations and the Paris Climate Agreement" in the future.

"There is an open invitation for the government, and all other political parties, to sign-up to these cross-party actions," the statement added.

It remains to be seen if Theresa May will accept the invitation, as the government continues to wrestle with escalating demands for it to drastically strengthen its climate strategy.