When I was asked to become minister for employment relations during the Coalition government, my first question was, “Do I get to deliver shared parental leave?”

The answer was yes, and I was over the moon. Giving mums and dads the opportunity to share their parental leave is one of my proudest achievements from my time in government. It is good for children, good for families and good for equality.

But it was not an easy win. As we tried to drive the policy through, we faced at every turn an onslaught of attacks from various Conservative Ministers – Grant Shapps in particular – who were intent on weakening or blocking the legislation.

It was quite exceptional to watch the Prime Minister this week claim credit for a long-standing Lib Dem policy that her colleagues had repeatedly tried to undermine – and for her to use it as proof for her party’s commitment to workers’ rights. What a joke.

Shared parental leave was not the only target for Conservative ministers, when it came to diluting employment rights.

First, there was the “report” written by Adrian Beecroft, whose venture capitalist background made him an odd choice for a review of workers’ rights. And, unsurprisingly, the report read like something a 15-year-old might bash out the night before a GCSE coursework deadline, with little understanding of the issues and the evidence.

But, given he was a multimillionaire Conservative Party donor, Beecroft’s ideas were given far more attention than they deserved. Some of his finest proposals included scrapping maternity rights and bosses being able to fire people for no good reason, on a whim. Vince Cable rightly told the Tories to take a running jump.

Others in the Conservative Party had their own ideas on how to make our labour market more “flexible”. George Osborne had a corker with his “shares for rights” scheme. Employees would be able to give up employment rights in exchange for shares. Thankfully we added protections so that no one would be forced to do so. And, frankly, business should share their successes with their workers, without asking them to give anything up.

Grayling was as incompetent then as he is now as transport secretary. He resolutely refused to budge on the Conservatives’ new employment tribunal fees or even review the irrefutable evidence that the fees were having a dreadful impact.

After a legal challenge by Unison, the Supreme Court eventually and thankfully struck down the fees as unlawful. The government should ensure workers have access to proper redress against rogue employers, it shouldn’t try to make it harder.

The list goes on. We stopped the Tories scrapping the Equality & Human Rights Commission and the Public Sector Equality Duty. We won battles to introduce naming and shaming for firms who fail to pay the minimum wage to their employees. And we hugely increased the resources for HMRC to clamp down on rogue employers paying less than the National Minimum Wage.

We stopped the Tories' extreme attempts to undermine the trade union movement, and the important work it does. After the 2015 election, the Conservatives immediately introduced the Trade Union Act 2016 - a nasty law to reduce the power and presence of trade unions in our workplaces.

The Conservatives also stalled measures on third-party harassment, relieving employers of some of their duty of care in cases where employees are harassed by, for example, customers. And they stripped workers of the ability to demand information that might help them in a tribunal claim.

Of course, many will argue about whether as Lib Dems, we picked, and won or lost, the right battles on workers' rights in the coalition. But what is not debatable is that these battles were constant.

These crusades were the product of many in the Conservative party seeing employment rights as unnecessary “red tape”. They were something to be pared back constantly, sacrificed on the altar of deregulation, with no attention given to evidence. But we all know that good business thrives when it treats its staff well.

Regardless of whether the Prime Minister is genuine in her intentions on workers’ rights, we all know her days in power are numbered. And she is deluded if she thinks that her “legal commitments” will protect employment rights from the axe of a future Conservative prime minister. I am so concerned that some Labour MPs can’t see right through her disingenuous, meaningless words and false comfort.

I would never trust the Conservatives on workers’ rights, having seen first-hand what they want to do with them – and I hope Labour colleagues won’t either. There is no such thing as a Brexit that protects jobs and workers. The only way to guarantee them is to stay in the European Union.

Jo Swinson is deputy leader of the Liberal Democrats.