Former Labour leader and Remain campaigner Lord Neil Kinnock has raised security concerns over the Supreme Court's historic Brexit ruling in January 2017.
The peer and ex-EU commissioner asked the government if they are "satisfied" that they have made "adequate arrangements" to safeguard public order in the vicinity of the court.
The 11 justices are expected to give a final decision over whether MPs will have a vote on triggering Article 50 – the official mechanism to split from the EU – after hearing an appeal from the government between 5 and 8 December.
Leave.EU had planned to stage a "100,000-strong" pro-Brexit protest outside the court on 5 December.
But IBTimes UK revealed the group had cancelled the demonstration amid fears far-right groups, such as the English Defence League, could hijack the event. Only tens of Remain and Leave activists turned up on the day.
Baroness Susan Williams, responding for the government, told Kinnock that police tactics and decisions are a "matter for the independent operational judgement of chief officers of police".
"The Metropolitan Police Service has a proportionate policing plan in place to maintain public order in the vicinity of the Supreme Court for the duration of the hearing of the Article 50 case," the Conservative peer added.
A Metropolitan Police spokesman told IBTimes UK: "An appropriate policing plan is in place."
Gina Miller, the lead claimant in the High Court case, has faced death threats in recent weeks.
The Remain-voting investment fund manager told IBTimes UK: "Yes there has been a deluge of hatred and anger but this is because people were lied to in respect to the EU referendum, and because irresponsible figures like [Nigel] Farage and tabloid media who lack any understanding of parliamentary democracy and the rule of law that is the bedrock of our civil society."
"As a philanthropist, my views are that advances in society, even democratic societies, require an unpopular act; otherwise progress would be easy. I cannot think of a better way to use my resources than to do what I believe to be right in preserving our democracy for everyone in the United Kingdom."
British Prime Minister Theresa May has promised to trigger Article 50 by the end of March 2017.