Twenty-five Liberal Democrat MPs tonight called on Charles Kennedy to quit as leader of the party.
In a statement issued tonight by education spokesman Ed Davey, the MPs said they wanted to give Mr Kennedy a "couple of days to reflect on his position" after saying they were not prepared to serve under him if he does not resign.
They added it was "absolutely clear that a growing number of MPs agree with us".
There are 62 Liberal Democrat MPs at Westminster.
The statement by Mr Davey said: "Everyone wishes to give Charles the weekend to reflect, and have expressed their sympathy and support for him in his battle with his serious medical condition.
"However, we felt we had to indicate what our personal intentions would be next week, given his statement yesterday.
"We have indicated to Charles Kennedy that we would no longer be prepared to serve under his leadership after this weekend and wish to give him the next couple of days to reflect on his position.
"Following conversations over the last few days it is absolutely clear that a growing number of MPs agree with us."
Local government spokeswoman Sarah Teather said she agreed with Mr Davey and that 23 other MPs had also indicated they could not serve under Mr Kennedy.
They are Norman Baker, Tom Brake, Andrew George, Sandra Gidley, Norman Lamb, David Laws, Jeremy Browne, Alistair Carmichael, Nick Clegg, Tim Farron, Lynne Featherstone, Julia Goldsworthy, Chris Huhne, Evan Harris, John Pugh, Jo Swinson, Stephen Williams, Nick Harvey, Martin Horwood, Dan Rogerson, Adrian Sanders, Matthew Taylor and Jenny Willott.Reuse content