Julian Smith admitted he asked Brandon Lewis to break pairing arrangement on crunch vote
Pressure is building on Tory chief whip Julian Smith to resign after it emerged he admitted to a rival that he had broken a parliamentary convention to help the Government win a key vote.
A furious row has erupted after it emerged that Conservative chairman Brandon Lewis broke a so-called "pairing" arrangement with Lib Dem deputy leader Jo Swinson, who has just had a baby.
Under the longstanding convention, an MP who cannot physically be in the Commons because of illness or maternity leave is paired with a colleague so as to cancel out their vote.
Both Mr Smith and Mr Lewis have insisted that they broke the arrangement on a customs union vote on Tuesday - which the Government won by just six - in "error".
But The Times reported that afterwards, Mr Smith conceded to another party's chief whip that he had instructed Mr Lewis to vote - but that he did not know he was paired with Ms Swinson.
PoliticsHome has also verified that Mr Smith made the admission.
Meanwhile, The Sun reported that Mr Smith approached up to five Tory MPs ordering them to break their pairs in the vote.
Lib Dem MP Christine Jardine said: “These allegations completely undermine the trust on which the pairing system depends. Cynical abuse to get the Government through a difficult day is a surefire way to corrode that trust.
"This situation is so serious that Downing Street can keep the system or they can save their chief whip. They can’t do both."
One former Tory cabinet minister told The Times that both Mr Smith and Mr Lewis should resign.
"Their behaviour is an affront to the very rules of conduct we have in our parliamentary democracy," they said. "They have both lied and have abused their positions in government to save their government jobs.
"They have brought into question the integrity of parliament and this government through such appalling conduct. They should resign."
The row is also embarrassing for Theresa May, who told the Commons on Wednesday the vote by Mr Lewis had been a mistake.
Jon Trickett, Labour's shadow Cabinet Office minister, has accused the Prime Minister of being part of a "calculated attempt" to mislead the Commons.
In a letter to acting Cabinet Secretary Mark Sedwill, he said: "These comments, as well as public statements issued by and on behalf of the Chief Whip, constitute a breach of the Ministerial Code as above, and should be investigated immediately.
"Please confirm as a matter of urgency that this has been referred to the Director General for Propriety and Ethics."