Julian Smith, the Tory chief whip, faced calls to resign over suggestions he intentionally ordered Tory MPs to defy "pairing" arrangements.
Some Conservative backbenchers joined Labour in saying he should quit if it is proved that the events that led to Brandon Lewis, the Tory chairman, breaking an agreement not to vote were intentional.
Meanwhile Dominic Raab travelled to Brussels for his first day of negotiations with the EU.
The new Brexit secretary took over from David Davis last week and has faced a difficult week as he attempts to win support for the government Brexit strategy agreed at Chequers.
One of the key sticking points in talks with Brussels is how the Northern Irish border will be managed, and Theresa May crossed the Irish Sea on Thursday to speak to residents and businesses working across the border. She was joined by Karen Bradley, the Northern Ireland secretary.
As it happened...