A report has warned a planned Holocaust museum next to Parliament would be a "gift" to terrorists.
Former ACPO national co-coordinator for domestic extremism, Adrian Tudway, said he believed the proposals created a "perfect storm of vulnerabilities".
Current plans are for a national memorial and learning centre in Victoria Tower Gardens; a park bordered by the Palace of Westminster, the river Thames and a main road through Westminster.
Mr Tudway's report has concluded the location is made more attractive as a target by the presence of Millbank studios opposite - home to the BBC, ITV and Sky News.
The former Met Detective Chief Superintendent told talkRADIO: "We are building a stage on which an extremist could carry out an attack right under the noses of the world's media."
The report has claimed a terrorist could "easily" attack the site in Victoria Tower Gardens and warned of the building's vulnerability to "suicide vehicle borne improvised explosive devices" and grenades being thrown from the road.
It said the memorial would be a "focal point" for extreme right wing groups and those with white supremacist or Neo-Nazi ideologies.
Another risk would be coach-loads of schoolchildren walking to the museum, it is claimed, as there is no place for a coach to park close by.
A government spokesperson said: "We are confident that the proposed site will be secure."
Opponents believe the location is inappropriate and want it moved to the Imperial War Museum less than a mile away.
talkRADIO has revealed Westminster planning officials are set to recommend the project is rejected. The goverment has already pledged £75 million towards the Holocaust museum.
In May then-Prime Minister Theresa May said: "By putting our National Holocaust Memorial and Education Centre next to our Parliament, we make a solemn and eternal promise that Britain will never forget what happened in the Holocaust."
Adrian Tudway's report was commissioned by the Save Victoria Tower Gardens group, which is campaigning for the museum to be relocated. He has insisted it was carried out independently, and a version of it has been submitted to Westminster City Council.
A spokesperson for the Ministry of Housing, Communities and Local Government added: “We are fully aware of the security implications associated and are in regular contact with Parliamentary Security, the Government Security Services, and the Metropolitan Police Service."