It may seem hard to imagine the Lib Dems overturning Mr Goldsmith's 23,015 vote majority, but they have been making waves in recent by-elections. Back in October, they slashed the majority David Cameron built up in Witney of 25,155 votes down to just 5,702 for his successor. They secured a swing towards them of 19.3 per cent from the Conservatives, leaving them in second place. A marginally greater swing - around 19.45 per cent - is all they need to win in Richmond Park.

Zac Goldsmith has his reputation as high-profile anti-Heathrow campaigner to fall back on, but the Lib Dems have worked to neutralise this by fielding their own anti-expansion candidate, allowing them to move the debate onto other issues that worry residents like Brexit.

Mr Goldsmith may have defeated the Lib Dems at two previous general elections, but he is now running as an independent, which means he will lack the Conservative electoral machine, and all the data it had gathered about voters in the area.

There are signs he is losing his electoral Midas touch. His dramatic failure to convince London to make him its Mayor earlier this year left him humiliated, forced even now to deny that he is a racist. Many voters in liberal, cosmopolitan Richmond will remember the controversial campaign he waged against Sadiq Khan.