Chris Grayling is MP for Epsom and Ewell, and Secretary of State for Transport.

As constituency MPs, we used to get regular emails from people telling us that we pay more money to illegal immigrants than to old age pensioners. Orthat MPs could build up a full pension entitlement in just one Parliament while our Armed Forces took many long years.

They were outraged, but both stories were completely untrue. The disturbing thing, though, was that the outraged constituents had fallen hook line and sinker for utterly false viral email campaigns.

Another campaign highlighted that the Chamber of the European Parliament was usually empty. It might perhaps have been true, but the pictures used were obviously taken in several different locations. It wasn’t difficult to spot.

But all too often people don’t look. They take what they read as gospel. And it’s a big challenge for us, because the biggest purveyors of fake news in Britain today are Momentum and the Labour Party. Time after time they push messages about us which are completely false, or which completely distort the truth.

In one recent example, they claimed that we rejected a Labour attempt to make it a legal requirement for landlords to ensure that their properties were fit for human habitation. The reality was very different. The Conservative bill gave local authorities more power than ever before to clamp down on rogue landlords. Labour’s headline chasing amendment was legally flawed.

But it made for an anti-Conservative campaign portraying us as heartless when we were the ones taking real action to solve the problem. And many believed it.

More recently, their campaign to claim that we thought that animals were not sentient only ground to a halt when several media outlets had to apologise to Michael Gove for misrepresenting our position. But not before many constituents had accused me and other MPs of not caring for animals.

We’re going to see much more of this fake-news approach to politics from Labour over the coming months and years. They will portray us as uncaring and unthinking, and will use false examples to make their case. Labour supporting think tanks will continue to pump out intentionally inaccurate information about the Government’s record. Hardly a day goes by without a Conservative MP reporting another outbreak of complete fiction from the left.

Such complete dishonesty in British politics is a very new feature. But it is a reality that we have to deal with. We will never convince the determined left of the falseness of their propaganda. But we have to sow real seeds of doubt into the minds of the reasonable people who see their messages. Quite simply, we have to discredit their fake news.

Gove did an excellent job of this over animal sentience. Jeremy Hunt has challenged his opponents successfully on Twitter. Lily Allen had to apologise when she made a false accusation about me over the collapse of Monarch Airlines. We will all have to learn to respond robustly when it is clear that a falsehood is gaining traction.

Every time we put the other side on the back foot and successfully expose their inaccuracies to those middle-ground voters, we damage the credibility of all their messages. Whether it’s highlighting Jeremy Corbyn’s u-turns on student finance, or forcing his left-wing cheerleaders to admit they were wrong, every successful challenge to Labour’s fake news undermines their other messages.

It’s something we will have to do relentlessly if we are to best them in the coming years.