Today the House of Lords will begin debating the government’s Counter-Terrorism and Border Security Bill. Like the many pieces of similarly named legislation passed by New Labour (two Terrorism Acts, the Anti-terrorism, Crime and Security Act, the Prevention of Terrorism Act, the Counter-Terrorism Act), it contains a number of new laws that amount to an unjustified and disproportionate reduction of civil liberties.

The bill would make it a crime – punishable by up to 10 years in prison – just to travel to certain places outside the UK specified by the home secretary. If you had a “reasonable excuse” for going (a term undefined by the bill), the burden would be on you to prove it.

It would also criminalise viewing online content that is “likely to be useful to a person committing or preparing an act of terrorism”. Journalists, academic researchers and the innocently curious could all face up to 15 years in prison for a single, harmless click.

The government asks us to trust it with these new state powers. It says it would only prosecute genuine terrorists. Yet recent history is littered with examples of anti-terror legislation being used against journalists, protesters and other innocent people, from Walter Wolfgang detained for heckling Jack Straw to David Miranda held for nine hours at Heathrow for helping the Guardian to report the Edward Snowden revelations.

ACT counter terrorism campaign video encourages public to report suspicious behaviour

The bill also expands a number of existing, illiberal state powers: to detain people at ports and airports without suspicion of any wrongdoing; and to hold innocent people’s DNA on record for several years. The government has failed to provide any evidence that expanding these powers will do anything to prevent terrorist attacks.

This legislation would, in short, do little to fight terrorism but a lot to destroy British freedoms. Parliament’s Joint Committee on Human Rights put it well when it said: “This bill strikes the wrong balance between security and liberty.” That’s why Liberal Democrat MPs voted against it in the House of Commons last month. As we filed through the “No” lobby, I confess I had hoped to see Jeremy Corbyn bringing his Labour MPs through with us. After all, he joined us on numerous occasions throughout the New Labour years to vote against similar laws being proposed by his own party: ID cards, 90-days detention without charge, the power to stop and search people without suspicion – the Liberal Democrats opposed each of these affronts to traditional British civil liberties, and Corbyn was one of only a handful of Labour MPs to vote with us every time.

I don’t agree with Corbyn on many things, but I always admired the courage and conviction he displayed in standing up to his own party’s government in defence of civil liberties. It was one of his defining causes during his 32 years on the backbenches. Indeed, it’s not long ago that he boasted that “I’ve been involved in opposing anti-terror legislation ever since I first went into parliament in 1983”.

But since becoming leader, Jeremy Corbyn has been notably absent in the fight to protect civil liberties. In 2016, he instructed his MPs to vote for Theresa May’s “snoopers’ charter”, which gave the government the power to collect and read everyone’s emails, texts and internet browsing histories. And last month, he ordered them to vote with the Conservatives to approve this latest assault. Indeed, only the Liberal Democrats and Green Party MP Caroline Lucas were left to oppose it, as the SNP failed to join us in the lobbies.

Now I have passed the baton to my Liberal Democrat colleagues in the House of Lords. We have an excellent team there who will be striving to stop this bill – or at least remove the worst parts from it. A number of influential crossbenchers have signalled their disapproval of the legislation too. But only if Labour actually opposes the government will we have any chance of defeating it.

The human rights group Liberty says that this bill “poses several significant threats to civil liberties and human rights” and “mistakes unreflective expansion of government power for evidence-driven responses to national security concerns”. The former director of Liberty, Shami Chakrabarti, now sits in the House of Lords as Corbyn’s shadow attorney general. I sincerely hope that she will listen to her former colleagues and join the Liberal Democrat peers in opposing these illiberal measures.

I have no doubt that, if Baroness Chakrabarti were not on the Labour benches in the House of Lords, she would be outside parliament campaigning for this bill’s defeat – just as she did for all those New Labour laws that we, together with Jeremy Corbyn, opposed. Now that she’s on the inside, hopefully she can persuade her leader to rediscover his principles, reverse his position and join the Liberal Democrats in our fight to stop the erosion of civil liberties.