The prospect of Boris Johnson leaving Number 10 before the year is out look increasingly likely today, with Smarkets indicating a 35% chance of the Prime Minister being ousted – up from 28% last night.

Following what can only be described as a challenging night for the Prime Minister’s leadership, Smarkets revealed that the results of the two by-elections were “broadly in line” with the expectations of the betting markets.

However, the betting exchange predicted that following the news of Oliver Dowden’s resignation as co-chairman of the Conservative Party, the likelihood of any further cabinet minister quitting this month is rated at 29%.

Matthew Shaddick, Smarkets Head of Political Markets, advised: “Thursday’s by-election results were broadly in line with the expectations of the betting markets. Conservative losses in both seats were priced in, albeit the Liberal Democrat majority was somewhat higher than polling-day estimates at Smarkets.

“Nonetheless, this is clearly bad news for Boris Johnson, and the chance of him being ousted from Number 10 this year rose from 28% to 35% as the results came in. Keir Starmer is the clear favourite to become Prime Minister after the next election at 43%.

“Oliver Dowden’s shock resignation immediately led to speculation about a possible cabinet coup. Smarkets’ early odds suggest that for now there is just a 29% chance that a further cabinet minister will quit before the end of June.”

The chances of the Prime Minister calling an early election currently stands at 6%, while the current favourite to become the next Conservative Party leader is Jeremy Hunt at 16%.