Parliament's dramatic 30-hour terror bill debate has led Liberal Democrat leader Charles Kennedy to cancel a visit to his Welsh party conference.
Initially he called off only part of his trip, to Bronglais Hospital, Aberystwyth, and had been due to speak in Cardiff on Friday night.
But he abandoned the whole trip when the Prevention of Terrorism Bill debate threatened to go into the weekend.
Welsh party leader Lembit Ípik was still hoping to be able to attend.
Mr Kennedy's hospital tour would have been in one of the Lib Dems' target seats, Ceredigion, and the conference is being held in another, Cardiff Central.
Mr Kennedy had been due to tell his party that there were no no-go areas for the Lib Dems, and that they offer a "real alternative" to Labour and the Conservatives.
The Lib Dems currently have two Welsh MPs, both in mid Wales: Brecon and Radnorshire and Montgomeryshire.
The party said it was convinced it could gain at least one seat in Wales, with its targets including Labour-held Cardiff Central.
In the last general election, incumbent Jon Owen Jones held it with a majority of 659.
The party won the Welsh assembly seat in 1999, and increased its majority in the 2003 election, and hopes to build on that result in the Westminster election.
Before the cancellation, Mr Kennedy had been due to visit Aberystwyth on Friday afternoon.
Mr Ípik, the MP for Montgomeryshire, said the debate in Parliament could affect MPs' plans to attend the weekend's conference but sacrifices had to be made.
"We will see what the government does," he said.
"The reality is these are such matters of principle, the Commons and Lords are so unhappy with how the government has been pushing this.
"Nationwide, not just in Wales but across the UK as a whole, MPs are striking their diaries for Friday, keeping a watching brief on Saturday because we are not going to be beaten by a process."