I never thought I’d see a student exchange programme trend on Twitter. People have told stories of studying and working abroad through Erasmus, sharing tales of friendships built, skills learned, and lives changed. Why? Because MPs voted against my amendment to keep the UK in Erasmus after the Brexit transition period. And people are angry.

The benefits of Erasmus are so obvious to the thousands of people who take part in the programme. Each year, more than 17,000 students at UK universities study or work abroad as part of their degree. They go because Erasmus has made studying abroad attractive and affordable. The EU gives them a monthly living grant, with young people from low-income backgrounds receiving higher bursaries and travel grants.

It really is an opportunity for everyone. College students, apprentices, adult learners, schools, youth programmes and teachers can all take part. Erasmus not only funds study abroad opportunities, but teacher training, partnerships between universities and colleges, as well as schemes to share best practice in education and youth policy.

Students who take part are more likely to find a job after graduating. One in three students who work during their placement get a job with their placement company after they graduate.

But what people remember most about studying abroad normally isn’t that they increased their employment prospects. They recall learning a new language, falling in love with the culture and building new friendships.

By voting against the Liberal Democrats’ amendment last week, Conservative MPs showed they are at least prepared to throw away all these benefits. It is devastating.

But the fight is not over. For a start, we’re trying again in the House of Lords. Today my colleague Mike Storey is expected to propose another amendment to keep the UK in Erasmus. It’s already been backed by crossbench and Green peers.

But there’s another reason to keep fighting. I don’t think the government has made up its mind about whether to stay in Erasmus or not.

At prime minister’s questions on Wednesday, Boris Johnson downplayed fears. “There is no threat to the Erasmus scheme,” he told MPs. “UK students will continue to be able to enjoy the benefits of exchanges with our European friends and partners.”

Certainly, the Brexit deal leaves open the door to the UK staying in Erasmus. Why then, just 24 hours earlier, did the secretary of state for education, Gavin Williamson, send out mixed signals? He told the Commons that Erasmus membership “will be a question for further negotiations” and that the UK would “develop our own alternative arrangements should they be needed”.

You would have thought that, three and a half years after the referendum, the government might have a clear position. But we’re reliant instead on the comments of a prime minister who has form in getting into trouble over off-the-cuff remarks. If Erasmus is really not under threat, why were Conservative MPs ordered to vote down our amendment last week?

The prime minister must now back up his words with actions. Universities warn that a UK-led replacement would find it impossible to match the reputation, brand awareness and sheer scale of Erasmus. We need a clear, unambiguous promise from the government to negotiate to remain a full member.

The sad truth is that we may never get any certainty about the government’s plans until it’s too late. Before the general election, the EU withdrawal agreement bill included a section forcing the government to publish its negotiating objectives. Now, that safeguard is gone. The government can negotiate what it likes, and Tory MPs will blindly vote for what’s in front of them.

Staying in Erasmus should be a no-brainer, yet we have a fight on our hands to save it. Liberal Democrats will campaign relentlessly to stop the Conservatives taking us out of Erasmus and many other vital EU programmes. We will not lot Boris Johnson weaken our education system and limit the horizons of our young people.