Labour MP Sir Keir Starmer has condemned the Trade Union Bill currently making its way through Parliament, saying it will be damaging to business and public service as well as workers if it passes into law.

At a debate hosted by Camden UNISON, the MP for Holborn and St Pancras spoke of his time as a human rights barrister, when he dealt with hundreds of trade union cases.

He said: “Many of those cases were people who were being injured in the same way, in the same workplaces and factories over and again, and only because those individuals were members of unions were they able to get compensation for the injuries they were sustaining.”

One of the earliest cases he dealt with was the miners’ strike, where he was instructed by Arthur Scargill over the pit closures, which he described as “an intense, deep dive into trade unionism”.

Sir Keir said he had experienced trade unions from both sides, because as a former Director of Public Prosecutions, he was the boss of 8,000 workers.

He said he had switched unions to join the same one as his staff to show solidarity and his belief in collective bargaining.

He said: “If you want to run a public service or a business, you need trade unions. If you’re negotiating with a trade union, it makes for a much better working environment and better outcomes for everybody.”

He said that for over a century, the law had increasingly intruded into trade union activity, and that the latest bill is “purely ideological” because it serves no real purpose.

The government says the trade union bill is necessary because of the number of transport workers’ strikes based on relatively low turn-outs in strike ballots, but Sir Keir pointed to the fact that industrial action has been steadily in decline for decades.

He said: “You have to ask yourself, what problem is this bill actually intending to solve?

“And there isn’t one. It is intended to strike simply at the heart of trade unionism and to extinguish the ability to take collective action.”

The Trade Union Bill has been described as the biggest crackdown on unions for 30 years, and seeks to criminalise “intimidatory” picketing and to allow employers to hire strike-breaking agency staff.

It will also limit the rights of workers to take strike action with a “double bind” threshold - meaning there must be a fifty percent turnout on strike ballots, as well as a majority in favour of industrial action.

Also at the debate was Lucy Masoud, a firefighter and treasurer of the London Fire Brigades Union.

She warned: “Firefighters are highly trained, and the idea that you can replace them with temporary, agency staff is dangerous to both the public and to those workers.

“Strike action amongst firefighters has always been an absolute last resort. I didn’t join the fire brigade to go on strike, but when I have done so, it has always been absolutely the right thing to do.

“The government tells us that we should show compassion and not strike, but where was their compassion when they closed ten fire stations in London?”

The TUC has called for a week of collective action against the Bill next month.

George Binette, Camden UNISON branch secretary, said : “I think it’s important to do something substantial during this week of action, in the context of a society which already has the most drastic restrictions on trade union activity, particularly strike action, in the western world, with the exception of a few states in America.”