The Tory party chairman has denied making light of Downing Street parties after donating a champagne bottle signed by the Prime Minister to a charity auction.
The item was advertised to bidders as a “souvenir of partygate” at an event in Hertfordshire.
A spokesperson for Mr Dowden confirmed he had donated the bottle, but insisted he had “no prior knowledge” of its controversial description.
This was confirmed by the charity behind the fundraiser, the Hertfordshire Community Foundation, as it apologised for “any offence caused”.
An image of what appeared to be a catalogue advertising the item to bidders was shared by the food critic Jay Rayner on social media.
It described the bottle as a “souvenir of partygate and the exemplary behaviour and morality of our dear leader”, noting that the donation was made by Mr Dowden.
Mr Rayner tweeted: “Perhaps you thought the Conservative Party took partygate seriously.
“Last night a champagne bottle signed by @BorisJohnson was donated to a charity event in Hertfordshire by local MP and Tory party chairman @OliverDowden. Read the description.”
Labour MP Chris Bryant added: “They really are laughing at us.”
Mr Dowden’s spokesperson said: “This item was donated in good faith several months ago for a local charity auction.
“Oliver Dowden had no prior knowledge of the description and this is obviously not his view.”
It is understood Mr Dowden’s team believe the description was written by somebody involved with the charity, and was not cleared by the Conservative Party.
Mr Dowden, the MP for Hertsmere, is thought to be angry the fundraising event had become tied up with politics.
Shabana Mahmood, Labour’s national campaign co-ordinator, said: “The industrial scale of rule-breaking in Downing Street is important no matter how much ministers dismiss it. They broke the rules and they broke they economy. Now they think it’s a punchline.”
In a statement shared on social media, Hertfordshire Community Foundation said: “This item was donated in good faith several months ago as part of a charity auction raising funds to support some of the county’s most vulnerable residents.
“The description was not drafted or seen by MP Oliver Dowden prior to the event. On behalf of the charity, we apologise for any offence caused.”