There was an awkward moment in Downing Street today when Boris Johnson’s pen ran out while he tried to sign the first £350 million cheque to the NHS.

The Prime Minister was eager to begin the untold benefits of Brexit with his first weekly post-EU payment to the health service, his side-of-a-bus pledge during the referendum campaign.

But after scribbling out today’s date, and ‘National Health Service’ in the pay line, his biro began to fade and stopped working at all after the word three on the second line.

Official Keeper of Government Pens Lorraine Fisher, 34, said: “It was a bit embarrassing.

“He still tried to sign his name on a cheque that was actually now for three pounds rather than £350 million.

“There were no more pens available as they were all held up on the other side of the channel, so he gave up and the NHS will need to struggle on as normal.

“It perhaps doesn’t bode well, but presumably he will sign a cheque for £700 million next week to make up for it.”

Political observer Alan Tasker added: “It’s like being robbed at ballpoint.”