“Nothing is off the table”. This was David Cameron’s thinly-veiled attack in 2013 at the beginning of the renegotiation of the UK’s EU membership. His intended target: the labour movement and the hard-won rights and benefits the EU has delivered for people in Britain.

The motivation for many eurosceptics in the Conservative Party (and, by extension UKIP)is to remove the blockages that the EU provides to extend their damaging domestic agenda. The EU acts as an essential block on many of their attempts to weaken workers’ rights.

The EU ensures the Tories cannot touch paid holidays, protected overtime pay for full and part-time workers, maternity and paternity rights and a host of other essential rights. The European Court of Justice, which upholds and ensures EU law,has upheld the right for workers to strike; something vital for those in fear of job losses or having their livelihood undermined.

Thanks to the insistence of trade unions and the Labour Party in the European Parliament the Prime Minister backtracked on his threat, leaving any mention of cutting workers’ rights or ripping up social Europe out of the draft document published last week.

But sadly this victory alone will not stop the Tories from doing what they can at Westminster. Taken together, if the Government were to rip up the European Convention on Human Rights (ECHR) and pass the Trade Union Bill, Britain would drop to the bottom of the pack for workers’ rights in Europe. Only the EU’s package of rights would prevent us from slipping still further behind other parts of the world.

The Tories are now engaged in a two-pronged attack on our rights at work.

The European Convention on Human Rights (ECHR) – which pre-dates the EU and which the UK helped to create –enshrines in law the right for workers to associate, organise and be represented and balloted by a union. Countries joining the EU must first sign up, though existing members may leave; none yet has. All EU Member States are signatories, including a further nineteen European countries, among them Russia.

The Government wants to opt us out of the ECHR and introduce instead a Tory-written ‘British Bill of Rights’.

British workers’ rights could be pushed into a position below that of workers in countries such as Lithuania and Estonia. If the Government is successful, it will mean that British workers and Unions will ultimately have fewer rights than workers living in some former Eastern bloc nations.

The second reason the Tories want to quit the ECHR is because it poses significant problems for the other prong of their attack: the Trade Union Bill.

The Bill introduces a number of attacks, including the requirement for strike leaders to wear armbands, carry a letter of authorisation and identify themselves beforehand to the police.

Proposals to allow the Government to scrutinise union membership lists have drawn comparisons with the methods of Romania’s former-despot Nicolae Ceausescu.

These comparisons stand in stark contrast to Romania’s own trajectory. Since gaining admittance to the EU in 2007 the country has seen a vast increase in the number of rights and protections afforded to its people.

At a time when countries across Europe are striving to improve rights for their workers, the Tories are working hard to undermine them.

The victory secured by the Labour movement during Cameron’s renegotiations is hugely significant. The EU can remain not just an economic union, but a social one too.

But having prevented a race to the bottom in world league tables, we must do everything we can to prevent the same happening in Europe. The UK must not become the European country that does the least to look after its own people.

Seb Dance is an MEP for London. This article is part of a series to mark heartunions, the TUC week of action against the Trade Union Bill.