The Conservatives have dropped five points in the latest poll of voting intentions.

The Tories are down to 40 per cent, while Labour are down one point to 37 per cent, an Ipsos Mori survey carried out between 16 and 22 April found. This was before the latest revelations from Dominic Cummings emerged.

The Lib Dems were polling up two points on 8 per cent while the Greens were unchanged on 5 per cent.

ITV host Robert Peston has waded into the No 10 vs Dominic Cummings briefing war – denying that the former top aide was the source of the leaked story on second lockdown plans last October.

“The “chatty rat” who contacted me was not Cummings,” Peston writes in his latest blog – discussing a message received from a government source on 30 October.

“I can tell you that the text was not from Cummings or anyone within a mile of him.

“And the reason I can share that with you, without breaching journalistic etiquette, should be obvious: if the text had come from Cummings, I would have put the news straight out, since he was a “horse’s mouth” authority on this stuff.”

Cabinet minister Ben Wallace has again defended Boris Johnson, claiming he wouldn’t have said the “let the bodies pile high” remarks attribute to him by an anonymous source.

The defence secretary told LBC: “That’s not my boss – my boss feels every difficult decision, because he knows about people, and he wants life to be successful for everyone … I’m proud to serve as him as prime minister.”

Labour had tried to get Commons Speaker Sir Lindsay Hoyle to grant an urgent question requiring a minister to come to the House to respond to the charge that Boris Johnson tried to get Tory donors to put up the money for the refurbishment work at Downing Street flat.

But it’s the SNP that has been granted an urgent question related to the “sleaze” scandal. Alison Thewliss MP will ask Cabinet Office minister Michael Gove to update the House on the ministerial code amid allegations of special access and cronyism.

Health minister Nadine Dorries has responded to Piers Morgan’s commentary on the anonymous accusation that the PM said “let the bodies pill high” rather than agree to another lockdown.

“It is an outright lie,” she said. “Not one substantiated fact or named source in that article.”

Zac Goldsmith, an environment minister, has joined her in the push back, tweeting: “He has never been casual about deaths. Suggestions to the contrary are an unforgivable lie.”

Sales of milk and cream to the EU are down an extraordinary 96 per cent – and chicken and beef by almost 80 per cent – in the past month, new figures show.

Overall, the trade barriers erected in Boris Johnson’s Brexit deal have cost exporters more than £1.1bn since the start of the year, the Food and Drink Federation has said.

The organisation said it was “essential” that the UK urgently seek a new agreement with the EU to resolve the problems.

But Brexit minister David Frost and his team have rejected the so-called “dynamic alignment” offer – which would see the UK aligns itself with Brussels’ plant, animal health and food safety rules – according to reports this morning.

Labour’s Kate Green said there were “very troubling allegations” surrounding the Downing Street refurbishment as her party called for a formal inquiry into the work was funded.

The shadow education secretary told BBC Radio 4’s Today: “It seems to me that as long as there is uncertainty, there is doubt and innuendo and rumour about who is getting contracts, who is paying for the refurbishment of the Downing Street flat, who is in and who is out … this is distracting the government.

“They are not getting on with the right priorities for the country because they are busy fighting among themselves and seeking to throw up smokescreen.”

In an apparent reference to the briefings battle with Dominic Cummings, Green said the government had been “fighting like rats in a sack”.

More questions for David Cameron to answer, perhaps.

The former Tory PM introduced an old Eton schoolfriend to a top adviser at the Department of Health and Social Care over a potential Covid contract last April, a new report has claimed.

Cameron introduced Etonian Hugh Warrender to “fixer” Andrew Feldman, working as a senior adviser at the Department of Health and Social Care (DHSC), according to The Guardian.

Warrender is said to have been representing a supplier of testing kits from South Korea keen to sell to the government.

Neither Cameron, Feldman nor the DHSC have yet responded to the claims.

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For all the latest on No 10’s paranoia over Cummings, Nicola Sturgeon’s second referendum strategy and UK-EU talks on the protocol, you can read today’s briefing here:

Two separate weekend reports cited anonymous officials’ claims that MI5 had probed the leaks about second lockdown discussions – the so-called “chatty rat” probe – and concluded that they came from Dominic Cummings’ sim card.

The Guardian’s Rafael Behr and Sky News’ Sam Coates are worried by the reports, and worried officials could be throwing claims around with any firm evidence. During their Twitter chat, Coates suggested political sources could be taking a bit too “loosely” about intelligence matters.