Tory MP Nick Boles leaves cancer treatment to vote on Article 50
Meanwhile Diane Abbott is understood to have asked Jeremy Corbyn for permission to abstain.
A Conservative MP has left hospital during treatment for cancer to support the Government in votes on Article 50.
Grantham and Stamford MP Nick Boles announced last autumn that doctors had discovered a cancerous tumour in his head.
His tweet today was the first since October, when he announced he was giving up Twitter while he undergoes treatment.
Boles was campaign manager for the unsuccessful Michael Gove leadership bid last year. Before that, he was a close ally of David Cameron and supported the Remain side in the referendum.
However he has now made clear his determination to vote through the Government’s bill to trigger Brexit.
In a post on his Facebook page, Boles said he was feeling “pretty grim” but he was determined “to represent my constituents on this important bill and do my bit to ensure that it is passed without amendment”.
Meanwhile, pressure is growing on the shadow home secretary to say whether she will vote for the bill at third reading.
A meeting of the shadow cabinet agreed this morning that there should be a three-line whip to back the Government's EU (Notification of Withdrawal) Bill on Wednesday evening.
That was despite a last-ditch attempt by shadow cabinet members Diane Abbott and Barry Gardiner for Labour MPs to be allowed to abstain on the crunch vote.
It means shadow business secretary Clive Lewis will almost certainly quit his post, and piles pressure on Abbott to either toe the party line or resign as shadow home secretary.
Abbott was criticised by some colleagues for missing last week's Article 50 vote after apparently suffering a migraine.
One MP who was present at the shadow cabinet meeting told PoliticsHome that chief whip Nick Brown had confirmed that Abbott had not asked for permission to go home and miss the vote.
The source said: “He also made clear that if you are too ill to go through the voting lobbies, you can sit in your office and be nodded through, meaning your vote is still recorded.
"He made it clear that the rules have to applied to everyone and that there can be no favouritism. The impression we got was that Nick was saying Diane would have to go.”