The warning comes after the US Congress in September overruled President Barack Obama's veto of the Justice Against Sponsors of Terrorism Act (Jasta).
Jasta, also referred to as the 9/11 bill, is expected to give families of victims of the September 11 attacks the opportunity to sue the Saudi Arabian government over its alleged links and connections with those involved in the attack, with 15 of the terrorists coming from the Gulf kingdom.
Britain could face a wave of claims from US lawyers as a consequence of America’s new Justice Against Sponsors of Terrorism Act (JASTA)— Absolute Legal Costs (@123_ALC) November 28, 2016
However, in a letter to the UK newspaper, the Telegraph, 21 senior UK political and military figures, including Col Tim Collins, Lord West, Sir Malcolm Rifkind, Lord Hain and Lt Gen Sir Simon Mayall, fear that the law will have a significant impact on the UK's counter-terror relationship with the US, and could lead to Britain being sued in American courts.
"Jasta erodes the centuries-old concept of sovereign immunity, giving US-based lawyers the ability to sue foreign states, including allies such as the United Kingdom, on mere allegations of negligence in tackling terrorism," the letter says.
'Jihadi John Victims Could Sue UK'
The British officials fear the legislation could even be used by families of the victims of former Daesh spokesperson Mohammed Emwazi, the British citizen known as 'Jihadi John' who allegedly took part in the executions of a number of Western journalists and aid workers in Syria.
If a law like #JASTA comes up in every country, every country will be sued by its biggest foe. UK by Argentina, Pakistan by India, etc.— _Tariq_ (@CaptainTariq) September 28, 2016
"For example, action could be brought against the UK government by victims of Jihadi John for our failure to prevent him from travelling to Syria."
"The Act consequently encourages the use of ambulance chasing lawyers in America due to the large and diverse number of suits that can be brought against foreign governments."
Jasta 'Opens Pandora's Box'
While the Obama administration was accused of bowing to Saudi diplomatic pressure in its opposition to Jasta, White House officials described the vote to overturn the president's veto as "the single most embarrassing thing the United States Senate has done."
In their letter, the concerned British figures said what started as a "noble endeavor" to secure justice for the victims of terror, has become a "threat to national sovereignty" that could weaken the international fight against terror.
So basically with Jasta effective, can Iraqis sue the US for the invasion? And can Palestinians sue the UK for giving Palestine away?— Firas Arafat (@firasarafatt) October 7, 2016
"The EU has warned that Jasta raises the 'inherent danger of causing reciprocal action' from the legislatures of other nations. This puts at risk not only the US, but the UK as well as it opens up a Pandora's Box of potential lawsuits that can come from anywhere."
The Jasta legislation has been a hugely controversial issue in the US, with Congress' decision to override Obama's veto causing a diplomatic crisis between Washington and Riyadh.
Riyadh has denied any role in the 9/11 attacks, with Saudi officials warning they could pull investments from the US if court cases are pursued.