The families of Troubles victims have told the Prime Minister the UK Government’s controversial legacy legislation is “an affront to all modern standards of decency”.

The Relatives for Justice group delivered a letter to 10 Downing Street, telling Boris Johnson the law will foster “division and hurt” rather than promote “reconciliation or healing”.

The group, who carried a coffin around Parliament Square and down Whitehall with the word Justice emblazoned across the top, said families have no confidence that the legislation will deliver “any semblance of truth”.

Protests also took place in Belfast and Londonderry as MPs debated the legacy plan in the House of Commons.

The UK Government has said the Northern Ireland Troubles (Legacy and Reconciliation) Bill aims to provide better outcomes for victims, survivors and veterans.

Introduced to the Commons last week, the draft laws offer immunity to people who are deemed to have co-operated with an information retrieval body.

The Bill would also stop future inquests and civil actions related to the Troubles, although it does not fully close the door to criminal prosecutions.

The proposed legislation has been widely criticised by Northern Ireland’s political parties, as well as victims’ campaigners, the Irish Government and Amnesty International.

To be forced to engage with this disastrous approach compounds the hurt and trauma of victims in a totally callous manner

On Tuesday, the delegation from Relatives for Justice, including chief executive Mark Thompson, gathered in a silent protest before delivering a letter to Number 10.

Before entering Downing Street the group walked in a funeral-like procession with placards reading “RIP human rights”, “RIP rule of law” and “RIP accountability”.

The letter to Mr Johnson said: “With this unilateral Bill your Government has shown a reckless disregard for the rights of bereaved families across the entire community, the Good Friday Agreement, the judiciary, the rule of law and the administration of justice.

“To be clear, if passed your Government will have acted in direct contravention of the law, the Human Rights Act and the European Convention of Human Rights.

“After such a protracted period of time to be forced to engage with this disastrous approach compounds the hurt and trauma of victims in a totally callous manner.

This is a devious, Machiavellian Bill. That's all that is, plain and simple. This is a smash and grab on justice and the rule of law and the Good Friday Agreement

“Prime Minister, this Bill is an affront to all modern standards of decency.

“Far from promoting reconciliation or healing, it will foster division and hurt.”

Mr Thompson concludes the letter saying: “While we value the opportunity of writing to you at this time, we would very much appreciate the opportunity to meet with you to explain our experiences of harm and conflict and why this Bill is so harmful.

“Meeting with families in person, from all backgrounds, affected by all actors to the conflict, would take little of your time but will explain why this Bill is universally opposed by victims and survivors across the community and receives no consent.”

After handing the letter in to Number 10, Mr Thompson told reporters: “For Boris Johnson and Brandon Lewis to tell families across the island of Ireland – and indeed the island of Britain, and further afield – affected by our conflict that this is in their best interest, this Bill of shame – how dare he?

“Shame on him. This is a devious, Machiavellian Bill. That’s all that is, plain and simple.

“This is a smash and grab on justice and the rule of law and the Good Friday Agreement that provides thousands of families, thousands of victims, their rights, which are now being effectively denied.

“We are not going away. We are the voices of our dead relatives and we will speak for them.”

Asked how hopeful he is about Mr Johnson meeting him and what it says about him if he does not, Mr Thompson said the Prime Minister is “hiding”.

Northern Ireland Secretary Brandon Lewis said he accepts the UK’s proposed laws will remain “challenging for some” but they are about trying to find a way to obtain information and provide accountability “more quickly and more comprehensively than the current system”.

He was opening the second reading debate on the Bill in the House of Commons.

Speaking about the proposed legislation, Sinn Fein president Mary Lou McDonald told reporters in Westminster: “It’s outrageous. This is a despicable piece of legislation. It’s not designed to give comfort to any victim or survivor.

“It is very cynically designed to draw down the shutters on victims and survivors, and it would make a despot blush.”

She said it cuts across “any notion of working collectively” and does not demonstrate the kind of impartiality and equality that is “at the heart of the Good Friday Agreement”.

Victims campaigner Raymond McCord, of the Truth and Justice Movement, said earlier that the only people who would benefit from the proposed legislation are the murderers and terrorists.

“The losers all round are the victims and their families,” Mr McCord told PA.

He said Mr Johnson, Mr Lewis and many other MPs treat families of Troubles victims as “daft Paddies”.

He said: “If they were at school and they were doing an O-level for Northern Ireland they would all fail. It’s as simple as that.

“And for people who went to university, they’re very uneducated people relating to part of the UK.

“They treat us as if we’re all daft Paddies. We’re anything but it.”

He said he was referring to Mr Johnson and Mr Lewis, as well as “many other MPs”.

Mr McCord added: “They really need to sit down and listen to victims’ stories, victims telling their stories. Not being told by the police, not being told by an MP for Northern Ireland or an MLA.”