Ukip expects that it will win this week’s byelection in Rochester and Strood, in a landslide so strong that it could lead to further defections from the Conservatives, reports have suggested.

The Telegraph reported on Monday that Ukip was forecasting a 15 point lead in the seat, which is being contested after ex-Tory MP Mark Reckless left his old party and joined Ukip.

Writing in the paper, politics professor Matthew Goodwin said that the “Tories have started too late and remain focused on a story about the national economic recovery, which even a quick look at the surveys would show is not being felt by most Ukip voters”.

In pictures: Rochester by-election Show all 15 1 /15 In pictures: Rochester by-election In pictures: Rochester by-election Rochester by-election Counting gets under way for the Rochester and Strood constituency by-election held at Medway Park, Gillingham, Kent In pictures: Rochester by-election Rochester by-election Nigel Farage and members of the UKIP team celebrate after Mark Reckless won the Rochester and Strood by-election at Medway Park, Gillingham near Rochester, Kent In pictures: Rochester by-election Rochester by-election Howling Laud Hope, leader of the Official Monster Raving Loony Party (R) awaits for the by election results in Medway, Gillingham Rochester, Kent In pictures: Rochester by-election Rochester by-election Kelly Tolhurst, the Conservative Party's candidate in the Rochester's by-election, walks down the town's high street on polling day, in southern England In pictures: Rochester by-election Rochester by-election Gulpreet Baines (18) sets fire to a United Kingdom Independence Party (UKIP) rosette, on polling day in Rochester's by-election In pictures: Rochester by-election Rochester by-election Naushabah Khan, Labour Candidate for the Rochester and Strood by-election is joined by shadow transport secretary Michael Dugher in Rochester on the final day of campaigning ahead of by-election In pictures: Rochester by-election Rochester by-election UKIP supporter Graham Harper and his dog Roquie carry a electoral poster supporting UK Independence Party (UKIP) parliamentary candidate Mark Reckless in Rochester, Kent ahead of the by-election poll In pictures: Rochester by-election Rochester by-election A customer poll of sweets purchased in favour of the party's contesting the Rochester and Strood by-elecction on display in the Sweet Expectations Sweet Shop in Rochester, Kent, on the final day of campaigning before the by-election later this week In pictures: Rochester by-election Rochester by-election David Cameron and Conservative Party candidate for Rochester and Strood, Kelly Tolhurst, talk to Mick Parks, Workshop Foreman at MCL Mechanical near Rochester, Kent, southern England, during a visit ahead of the by-election In pictures: Rochester by-election Rochester by-election People stand holding placards against the Britain First party who held a march in Rochester, southeastern England In pictures: Rochester by-election Rochester by-election Britain First march through Rochester Justin Sutcliffe In pictures: Rochester by-election Rochester by-election UKIP parliamentary candidate Mark Reckless campaigns in Rochester on November 4, 2014 Rob Stothard/Getty Images In pictures: Rochester by-election Rochester by-election Ed Miliband campaigns with Yvette Cooper (left) and Naushabah Khan before the Rochester and Strood by-election Ben A. Pruchnie/Getty Images In pictures: Rochester by-election Rochester by-election The Britain First march was met by vociferous counter protest Justin Sutcliffe In pictures: Rochester by-election Rochester by-election A UKIP office in Rochester. Rochester and Strood will hold a by-election on November 20th following the defection of Conservative Party Member of Parliament, Mark Reckless to UKIP Rob Stothard/Getty Images

The Observer this weekend claimed that the Tories had given up hope of winning the seat, and were instead working to keep the margin of victory below 10 points. Reports claimed that Tories were making the admission to limit the shock of a big defeat in the byelection on Thursday.

Polls have long predicted a Ukip landslide in the seat, with one showing last weekend that the party is enjoying a 12 percentage point lead over the Tories.