London’s major political parties candidates for mayor were left shocked, as NHS England announced it wouldn’t roll out PrEP.

Told during a question at the Pride in London hustings on Monday night that the health body would not roll out the drug, all candidates hit out at the decision.

It was later clarified to them that the decision was in fact to extend the trial to “early implementer test sites” for two years.

Having come out in favour of PrEP in an interview with PinkNews, the Conservative’s Zac Goldsmith said it was “a massive missed opportunity.”

“I don’t pretend to be an expert, but I have looked into this issues and it’s an unavoidable no-brainer,” he said.

“All I can tell you is I will take that news and use whatever influence I can as a backbench MP and a candidate for Mayor and try and persuade the government to intervene.”

The Green’s Sian Berry said her party made decisions based on evidence and the facts showed PrEP worked.

She said: “This is deeply worrying news.

“It’s clear there is evidence that shows PrEP makes a difference. It clearly does reduce harm and that [decision] is deeply worrying.”

The Camden councillor added that as mayor she would “try and find more evidence” in order to get the decision changed.

UKIP’s Peter Whittle believed the role of mayor was as an “unique influencer” and if elected would use the position to campaign the NHS to change its decision.

“As a gay man, I would absolutely take it as my duty, my moral duty and privilege, to talk about these issues,” he told the room.

“Why wouldn’t you put PrEP on the NHS, why wouldn’t you given that it saves lives.”

The 55-year-old responded to comments that his party had advocated banning people with HIV coming to Britain, as stopping “health tourism” and added that he would push for PrEP to be on the NHS.

Sophie Walker, the Woman’s Equality Party candidate who was added to the lineup earlier on Monday, said: “I don’t think I’ll differ from what the rest of the panel has said.

“This is a shock and is quite a strange decision by the NHS. I think that any of us as Mayor would use the leverage we have to try and reverse that decision.”

Ms Walker added that she believed schools should have compulsory sex education.

The Liberal Democrats’ Caroline Pidgeon was the most notably annoyed at the NHS decision.

She said: “PrEP absolutely needs to be available on the NHS.

“It’s the NHS’ job to make people healthy and safe and it’s really wrong for the NHS to have made this decision and I’m really quite shocked by it.

“It’s vital that we give people things they need to be as safe as they can be and whatever they choose to do in their lives.

“It’s a step back for the NHS to have made this decision.”

Tooting MP and Labour nominee, Sadiq Khan, said that the move “beggars belief”.

“Putting aside the studies here and in the US that have shown it’s positive or the social or moral case…it just beggars belief,” he said.

Mr Khan raised the fact that education was important because as many as 25% of gay men in London have HIV and don’t actually know it.

He also attacked the government for cuts to the public health budget in London.

Responding to questions about the decision today in the chamber, Parliamentary Under Secretary of State for Public Health, Jane Ellison MP, said they recognised that the decision could have been taken earlier and that the Government would work with the NHS to take “what they’ve learned forward”.

Mayoral and the Greater London Assembly elections take place on May 5.