The Labour leadership is facing claims it is being defeatist over he Rochester and Strood by-election, a constituency it held for 13 years up until 2010.

Reports suggest the national party is downplaying its chances of winning and does not intend to plough resources into what it considers a two-way battle between Ukip and the Conservatives.

According to The Guardian, officials have angered local party activists over its stance because they believe it could be winnable.

The seat was the last of the three Medway constituencies to select a candidate with Naushabah Khan being chosen less than a year ago, although she has an advantage over the Tories who are sacrificing campaigning time by choosing their nomination by a postal open primary.

Labour has never made any secret that it has to win key Kent constituencies if it is to form a government but has just two official targets: Dover and Deal along with Chatham and Aylesford. Rochester and Strood is outside the 106 target Labour seats at 129.

Luke Akehurst, a former NEC member, wrote in a blog for the website Labour List that the party should be working harder to win: “Isn’t the job of party high-ups be they officials or senior politicians to devise strategies, tactics and messages that stop our vote going to UKIP and attract additional support to Labour, rather than issuing defeatist briefings that undermine the CLPs and candidates in the frontline?”

“If they don’t have the audacity and self-belief to win, they need to resign and let people with some fire in their bellies give it a go.”

He went on: “At the moment we seem to have an electoral strategy designed by Mr Micawber. ‘Something will come along’ (the tooth fairy?) to gift us a narrow victory on a 35% vote share thanks to flaws in the voting system.”

Vince Maple, the Labour group leader on Medway Council, said: “We are getting strong support [for the campaign] from our regional organisers and we are absolutely up for the fight. The strong message on the doorstep is the NHS, particularly because of the situation at Medway Hospital.”