An exclusive Business Insider / GfK election poll shows the Conservatives on 48%, Labour on 28%.

Theresa May is heading for a huge majority on June 8.

The Tories lead Labour among all social classes.

Approval ratings: May +16 / Corbyn -30.

Still no sign of a surge for the Liberal Democrats.

LONDON — The Conservatives remain headed for a landslide victory in the general election, an exclusive Business Insider / GfK opinion poll shows.

The survey conducted by GfK shows that 48% of Brits intend to vote for Theresa May's Conservatives on June 8, which is a 7-point increase for the Tories since GfK's last opinion poll. Twenty-eight percent of respondents said they plan to vote for Labour.

If these results were repeated at the general election, the Tories could expect to win 406 seats, leaving Prime Minister May with a huge working majority of 162 MPs, according to Martin Baxter's Electoral Calculus.

Here are the results of our general election voter intention poll:

Conservatives: 48% (+7)

Labour: 28% (no change)

UKIP: 5% (-7)

Lib Dem: 7% (no change)

Green: 3% (-3)

Other: 8% (+2)

The Business Insider / GfK survey is just the latest poll to give the Conservatives a double-figure lead over Jeremy Corbyn's Labour. Here's look at how the Tories have enjoyed a comfortable lead over Labour in the polls ever since May announced a snap election on April 18.

The Tories also lead Labour among all social classes and have a 48 percentage-point lead among respondents who voted Leave in June. Labour leads the Conservatives among people who voted Remain — but by only 6 points.

"Jeremy Corbyn’s approval rating has improved since our last survey in March but it will be of little consolation to Labour supporters considering the Conservatives extremely large lead," GfK Research Director Keiran Pedley said.

"It is too early to make specific predictions about what might happen on June the 8th with three weeks to go – surveys of this kind are a snapshot of opinion rather than predictions as the saying goes – however, given Theresa May’s strong approval ratings and the size of the Conservative lead it really would be a shock if the Conservatives didn’t win this General Election with a significantly increased majority."

The increase in support for the Tories appears to come at the expense of UKIP, which has lost 7 percentage points since GfK's last voter intention opinion poll in March. There is still no sign of any sort of surge for Tim Farron's Liberal Democrats.

Corbyn's personal ratings continue to be a big problem for the Labour leader. Asked how they thought Corbyn was handling his job as Leader of the Opposition, 52% said they disapproved, while 22% approved. Compare this to May, whose handling of her role as Prime Minister was approved by 49% of respondents, while 33% disapproved.

Corbyn's approval rating has improved by 5 points since GfK's last survey but was still the worst of all party leaders.

Corbyn's approval ratings remain negative but he is nowhere near as toxic as Tony Blair.

The former Labour Prime Minister announced earlier this month that he wants to return to British politics to fight Brexit but the results of our opinion poll suggest wouldn't be welcomed back by the British public.

Blair received a net score of -38% when respondents were asked whether they'd consider voting for a Labour Party under his leadership. Corbyn's own net score was -22%, which was better than Ed Miliband who scored -32%.

The Business Insider / GfK survey found little obvious change in voter perception of Brexit since the company's last poll. Forty-five percent (-1%) of respondents said the decision to leave the EU was the right decision while 41% (no change) said that it was wrong.

GfK surveyed a nationally representative sample of 1,952 British adults online between May 3 and May 14