Liberal Democrats
A poster supporting the Liberal Democrats is displayed in the constituency of Witney Matt Cardy/ Getty Images

By-elections are notoriously hard to predict. The playbook has different rules, the results don't follow normal predictors, electors have altered considerations. The imminent Richmond Park by-election, triggered by the resignation of Zac Goldsmith in his opposition to Heathrow, is a two horse race between the incumbent (now standing as an independent) and the soon to be selected Liberal Democrat candidate.

The unsuccessful London Mayoral candidate won Richmond Park with one of the largest majorities of last year's General Election. Much like the rest of the country, the swing away from the Liberal Democrat candidate was substantial, with my party trailing Goldsmith.

However, earlier this month, Liz Leffman won the biggest swing to a Liberal Democrat in decades in the campaign for David Cameron's former seat of Witney. Incidentally her swing of 19.2% is almost identical to the vote swing the Liberal Democrats would need to win Richmond Park now.

The question is: can we win?

The people of Richmond Park are vociferously opposed to any Heathrow expansion. That is the issue on which Goldsmith resigned. Unfortunately for Goldsmith, the Liberal Democrats have staunchly and vociferously opposed any expansion of Heathrow for nearly twenty years. I know, because I announced this position at our autumn conference in 1997, soon after I was elected for the first time.

So this battle for Richmond Park will not be about Heathrow, as the two strongest contenders are against Heathrow expansion. It will be a plebiscite on Theresa May's government, Theresa May's response to Brexit, Zac's support for Brexit and possibly on the conduct of this year's Mayoral election. On each of these points, I believe the country and the electors of Richmond Park are on the side of the Liberal Democrats.

We won't be saying that we want to ignore the result of the referendum. We will be saying that Theresa May's strategy is not the best way forward.

Richmond Park voted to stay in the European Union with one of the highest margins in the country. Goldsmith was a staunch opponent of the UK's EU membership, citing that "Britain will flourish or at least not be disadvantaged by leaving the EU." I don't think residents of Richmond Park need me to point out how wrong he has already been proven on that count. The pound recently hit a 168-year low against the dollar, the British Chamber of Commerce has halved its growth predictions for next year, and Lincolnshire company Smiffys is moving their headquarters to the Netherlands, after 120 years in Britain, citing the uncertainty caused by the Government's approach to Brexit.

The Liberal Democrats won't be saying to the voters of Richmond Park that we want to ignore the result of the 23<sup>rd of June or rerun the referendum. We will be saying that Theresa May's strategy is not the best way forward. Those living in Richmond know that May's strategy is damaging. They know it is doing more harm than good. The voters know that re-electing Zac Goldsmith as an independent MP will not change the decision on Heathrow. And they know it is a proxy of approval for the Government's Brexit plan.

This by-election offers the voters of Richmond Park the unique chance to emphatically state their disapproval for the Government's hard Brexit road map. May's path is not what people voted for in June and she has set us in a disastrous direction. A vote for Zac Goldsmith is a green light for the Government to continue full steam ahead. A replica of the vote swing to the Liberal Democrats in Witney would be enough to elect our candidate; a stark warning to the Government. This referendum has given residents of Richmond Park an awesome responsibility. The Liberal Democrats are working to ensure that responsibility can be fulfilled.

Tom Brake is the Liberal Democrat MP for Carshalton and Wallington.