A Conservative MP has been arrested on suspicion of rape and the possession of controlled substances.
Surrey Police said the man was detained on Wednesday morning in Horley.
The Tory party has declined to comment on the arrest, first reported by The Sun.
A police spokesman said: “We can confirm a man was arrested yesterday morning (October 25) in Horley on suspicion of rape and possession of controlled substances.
“He has been released on conditional police bail pending further inquiries.”
The by-election in Tamworth saw Labour overturn a 20,000 majority to take the seat in Staffordshire, which has been held by the Tories since 2010.
The constituency was left vacant by former deputy chief whip Chris Pincher, who quit parliament in disgrace after losing his appeal against a suspension from the Commons following groping allegations.
The Labour Party also took Mid Bedfordshire from the Conservative in a bitter battle with the Lib Dems.
The contest Mid Bedfordshire kicked off after the resignation of former culture secretary Nadine Dorries, who resigned in anger at being denied a peerage in Boris Johnson’s resignation honours list – but did not officially vacate her seat for 81 days.