The Conservatives will not contest the Batley and Spen by-election as a mark of respect for Labour MP Jo Cox, who was killed yesterday.

A by-election to replace Cox will eventually be held, but a party spokesman confirmed the Conservatives would give Labour a free run at the seat.

Cox won the seat in 2015 with 21,826 votes in 2016 and the Conservatives were second with 15,769 votes.

A Tory spokesperson said: “Following the tragic killing of Labour MP Jo Cox, the Conservative party has decided not to contest the forthcoming by-election as a mark of respect to a much-loved and respected politician.”

The decision not to contest a Commons seat is not unprecedented, since Labour and the Liberal Democrats refused to stand candidates in a by-election triggered by the resignation of Tory MP David Davis in 2008. Davis had quit in protest over Labour proposals to extend the length of time terror suspects could be held by the authorities without charge.

However, after Conservative MP Ian Gow was killed in 1990 – the last serving MP to suffer such a fate – the main political parties contested the by-election in his Eastbourne seat as normal.

Gow was murdered by the IRA and all parties put forward a candidate arguing that democratic politics should go on as normal. The seat was then unexpectedly won by the Liberal Democrats.

The date of the Batley and Spen by-election will be set when Labour moves the writ to schedule it in the House of Commons.

The news that the Tories will not contest the by-election was confirmed at 1pm on Friday - some hours after a call on Thursday night by former Tory chairman Grant Shapps.