Aides to Boris Johnson have been instructed that all briefing memos for the Prime Minister should be kept to two sides of A4 paper to improve the chances of him reading them.

The Downing Street policy unit was said to have been asked to provide the PM with 'weekend reading' but was told any documents had to be an 'easy read'.

Meanwhile, the PM's top aide Dominic Cummings is apparently blocking documents due to be placed in the premier's ministerial red box if he deems them to be too long or complex.

The claims, reported by the Sunday Times, sparked a backlash as Whitehall sources suggested those running the government were operating as if they had attention deficit hyperactivity disorder.

Aides to Boris Johnson have been told to keep memos to the PM short to boost the chances of him reading them

Mr Johnson spent all of last week working from the grace and favour Chevening estate in Kent as he was criticised for staying at the country house instead of visiting flood victims.

The Number 10 policy unit was apparently asked to provide the premier with memos on different policies so that Mr Johnson can be fully across proposals.

But a source said the instructions were clear that the documents must be kept as brief as possible.

They said: 'They've been told it should be an easy read: no more than four pages, or he's never going to read it. Two pages is preferable.'

The PM's red box is filled every day with crucial documents and briefings for him to read.

But Mr Cummings is said to have taken a strict approach to what is allowed to go into the briefcase.

An official said: 'Box submissions have to be brief if he is going to read it.

'If they're overly long or overly complex, Dom sends them back with savage comments."

Dominic Cummings, pictured in Downing Street on February 20, is said to be restricting what is put into the PM's ministerial red box with briefings deemed to be too long sent back to who wrote them

A Whitehall source told the Sunday Times it was 'government by ADHD'.

It came as David Davis, the former Brexit secretary, criticised the government for reportedly coming up with a 'hit list' of senior civil servants it wants to replace as he also hit out at Mr Cummings.

Mr Davis said current issues in the civil service would not be resolved with a 'firing squad'.

Mr Cummings previously described the former Cabinet minister as 'thick as mince' and accused him of being as 'lazy as a toad'.

Mr Davis today hit back, telling the BBC's Andrew Marr Show that Mr Cummings was not likely to be in a position of power for very long.

'I mean, Cummings doesn't like me, I know that, that's self-evident, but frankly he's a special adviser - here today, gone tomorrow,' he said.