The Prime Minister's intervention comes amid mounting concern over excessive surcharges across large swathes of the country.

A "Statement of Principles" was introduced by the UK Government in 2014 in an effort to force firms to ensure they charge fair prices for deliveries.

But Citizens Advice Scotland this week warned online shoppers in northern Scotland pay a "postcode penalty" of between 30 per cent and 50 per cent more than the rest of the UK.

The Scottish Government has powers over consumer advice and advocacy and only the UK Government can regulate parcel deliveries.

Holyrood Business Minister Paul Wheelhouse has called for greater regulation.

Mrs May today signalled UK Business Secretary Greg Clark would look at the problem as the CAS research was raised by Moray MP Douglas Ross whose constituents regularly face "ridiculous prices".

The Prime Minister said: "I'm sure he knows that Royal Mail does provide a universal postal service that includes parcel services five days a week at a uniform price throughout the United Kingdom but there are commercial issues that play outside this service.

"But I am sure that my Right Honourable friend the Business Secretary will be happy to meet with him and discuss this issue."

It came as former Rural Affairs secretary Richard Lochhead lead a Holyrood debate demanding that all firms are forced to adopt set standards for deliveries to each and every corner of the UK.

Moray MSP Mr Lochhead, who launched the www.fairdeliverycharges.scot website, has attracted around 1,600 signatures on his petition to tackle the problem.

Mr Lochhead told MSPs: “December 2017 will go down as a turning point, when people will say enough is enough and authorities will accept that real action has to happen.

"Many household and businesses are ripped off by jaw dropping and completely unjustifiable charges for delivery."