Blue is the colour! The Queen looks radiant in the spring sunshine as she unveils a plaque in London to mark centenary of the UK's security agency
- Monarch, 92, unveiled centenary plaque at Watergate House in London today
- Marked 100 years of GCHQ, the UK's Intelligence, Security and Cyber Agency
- Wearing a royal blue coat and co-ordinated hat, Queen looked on sparkling form as she joked about 'scrambler' phones her father, George VI, had used
- It was revealed this morning that the Duke of Edinburgh, 97, won't face charges for the car accident he had in January near the Sandringham Estate
Wearing the brightest shade of blue, the Queen looked to be enjoying an early glimpse of spring sunshine as she arrived for an event in central London this morning.
The Queen, 92, chose a royal blue coat with a matching hat adorned with a colourful green feather and brooch flourish as she arrived at the headquarters of GCHQ, the UK's Intelligence, Security and Cyber Agency.
At low-key Watergate House, close to Charing Cross Station, the monarch smiled at well-wishers as she unveiled a racing green plaque to mark the centenary of the agency, which she has regularly received intelligence from throughout her life.

After being gifted a bunch of spring flowers including miniature daffodils, the Queen chats with Jeremy Fleming, Director of the GCHQ, as she prepares to unveil the plaque

A colourful flourish adorned the royal blue hat of the Queen, 92, as she arrived at Watergate House in London this morning to unveil a plaque commemorating a centenary of the UK's Intelligence, Security and Cyber Agency

Pulling back the ochre velvet curtains, the Queen, 92 reveals the green plaque at Watergate House, which lies close to Charing Cross Station in Central London

Collaboration: The brand-new plaque offers a history of the GCHQ, which was formed from previous security organisations including The Admiralty's Room and The War Office

Despite the early morning chill, the weather in central London played ball, bathing the offices with bright sunshine (Pictured: Jeremy Fleming and the Queen outside the GCHQ headquarters)

Ahead of the unveiling, GCHQ Director Jeremy Fleming spoke to gathered crowds saying the security services in the UK had a history of solving or harnessing 'some of the world's hardest technology challenges'

The Queen listened to Jeremy Fleming as he said: 'Our work is not often glamorous or easily portrayed in film'

Japes: The Queen shares a joke with an employee of the GCHQ as Director Jeremy Fleming (far left) looks on
Earlier today, it was announced that the Duke of Edinburgh wouldn't face prosecution for the car accident he was involved in close to the Sandringham Estate in January.
Arriving at the understated central London address, the Queen was gifted with a bunch of spring flowers including miniature daffodils as she chatted with Jeremy Fleming, Director of the GCHQ.
She finished her bright blue ensemble with her favoured black loafers, black leather handbag and a pair of black woolen gloves. A stunning brooch and three-tier string of pearls added a hint of regal glamour.
On the steps outside the building's exterior, she pulled back a pair of ochre velvet curtains to reveal a green plaque honouring the UK's security agency.
The Queen has been receiving intelligence from the agency for much of its existence - but she joked how her father King George VI would become frustrated with his scrambler phone, modified by GCHQ to make his calls secret.

Security! The Queen walks past a close protection officer in the building as begins a tour of the GCHQ's offices

The Queen wore an elaborate adornment on her royal blue hat which combined precious stones and green feathers

The green and white lacquered plaque which marks one hundred years of the GCHQ. The understated central London address provides intelligence to high-profile UK figures

A.I here we come: The Queen heard about modern advances in security including technologies like artificial intelligence and quantum computing

The Queen has regularly received intelligence from throughout her life and joked about the 'scrambler' phone her father, King George VI, was forced to use

She told Jeremy Fleming: 'I remember my father had one, he used to get so cross when it didn't scramble'
GCHQ's director Jeremy Fleming, speaking at the agency's former London home, told the Queen and invited guests: 'Our work is not often glamorous or easily portrayed in film.
'But over the last 100 years it has saved countless lives, shortened wars, given Britain an edge, and solved or harnessed some of the world's hardest technology challenges.'
Among the guests for the Queen's unannounced visit were Alex Younger, chief of the Secret Intelligence Service (MI6) and known as 'C', and Andrew Parker, director general of MI5, the Secret Service.
Mr Fleming added: 'It's clear to us all that the world is changing at an unprecedented rate. It's more interconnected than ever before.

Accessorising with a pair of black gloves and her trusty black leather handbag, the Queen chatted about the organisation's role in British security (pictured: the Queen with Jeremy Fleming, Director of GCHQ)

The Queen also met Ruth Bourne, 92, a former Bletchley Park code breaker, after unveiling the plaque

The head of GCHQ told the Queen that the agency has 'saved countless lives' and 'shortened wars'
'And this is driving extraordinary opportunity, innovation and progress. It's also unleashing amazing complexity, uncertainty and risk.
'To keep up in this digital era - to optimise the potential of technologies like artificial intelligence and quantum computing - we know we need to keep reinventing.'
During her visit to the nondescript office block near Charing Cross station, the Queen met Ruth Bourne, 92, a former Bletchley Park code breaker.
When the subject of scrambler phones - used to keep important conversations confidential - was mentioned, the Queen said: "I remember my father had one, he used to get so cross when it didn't scramble.
'Took some time to heat up and then work.The machines used valves, today replaced by transistors, which needed time to warm up before the equipment would work.'
The head of GCHQ said his agency has 'saved countless lives' and 'shortened wars' as the Queen celebrated the 100th anniversary of the intelligence, security and cyber organisation.