For now, while Patrick Mercer is no longer  a Conservative member of parliament, he remains an MP. But having resigned the whip over an alleged lobbying scandal (due to be reported by the Telegraph and Panorama), it remains uncertain whether he will be able to hang on until 2015, raising the possibility of a by-election in Newark.
Mercer, who has said he will stand down at the next election, has a majority of 16,152, but given UKIP's recent performance, the party would hope to challenge the Tories for victory in a seat which neither Labour nor the Lib Dems can realistically win. UKIP only polled 3.8 per cent in 2010, but won 17.1 per cent of the vote in the Newark & Sherwood District in this year's county council elections. And, as ever, there is no such thing as a safe seat in a by-election.
Incidentally, this case is another example of why a recall law is badly needed. As Zac Goldsmith points out , "If it's bad enough for you to resign from your party, how can it be ok to continue representing constituents at all? Where's that Recall?!"