At a news conference, Zia Yusuf, Reform's home affairs policy chief, accused other politicians and the media of fuelling hostility towards the party, which, he said, had led to death threats against Farage and other MPs.
Paying tribute to Widdecombe, a 78-year-old former Conservative minister who was found murdered in her home on July 9, Yusuf said MPs needed better security provision.
A British man has been arrested.
"If Reform win the next general election ... I will ensure that all members of parliament, of all parties, are provided with round-the-clock protection," Yusuf said on Wednesday.
"We will also allocate significant new resources to protect former politicians still active in public life."
In Britain, politicians are no strangers to abuse from the public, but in recent years many MPs have said the tone has become increasingly ugly and dangerous, with some changing their routines and behaviour to avoid confrontation.
In 2021, Conservative MP David Amess was stabbed to death in a church by a man inspired by Islamic State.
Five years earlier, Labour MP Jo Cox was shot and stabbed by a Nazi-obsessed attacker during the Brexit campaign.
Yusuf said Farage, who is under pressure over funds he received from wealthy donors, had received almost 600 death threats since February.
That was why, he said, Farage had accepted donations to fund his own security detail — an argument, among others, the Reform leader has used to justify his acceptance of a Stg5 million ($A9.6 million) donation from a billionaire cryptocurrency investor.
"Those who question Nigel Farage's need for security should stop," Yusuf said.
Security measures were bolstered after Cox's murder, with MPs offered panic buttons and additional locks at their homes and offices.
After Amess' murder, the Conservative government and parliament offered MPs trained security protection when meeting voters.
