Ukip is on track to take the Thurrock constituency, according to the latest polling.

Nigel Farage claimed his party was set to “make history” as polling by the Conservative former treasurer Lord Ashcroft gave them a four point lead over Labour.

The poll places Ukip candidate Tim Aker is on 35 per cent support, against Labour’s Polly Billington – formerly an advisor to Ed Miliband – on 31 per cent in second place and incumbent Conservative Jackie Doyle-Price on 30 per cent.

Mr Aker, who has urged Conservative voters to support him and keep Labour out, said: "This election is a straight fight between me and Ed Miliband's candidate. Voting Tory in Thurrock achieves nothing except help Ed Miliband's candidate.

"As the only local candidate, I hope Thurrock residents lend me their support so that we can take back control and turn this borough around.”

Nonetheless, the three parties remain within five points of one another in the tightly fought seat.

The polling data, released earlier today, examined six marginal seats – Bristol North West, Bristol West, Rochester and Stroud, Colne Valley and Thurrock.

Despite their dispiriting showing in the Thurrock polls, the Conservatives were predicted to be back on course to re-take Rochester and Stroud – lost after Conservative Mark Reckless defected to Ukip.

The Independent has got together with May2015.com to produce a poll of polls that produces the most up-to-date data in as close to real time as is possible.

Click the buttons below to explore how the main parties' fortunes have changed: