Detective Chief Inspector John Turner, who is leading the investigation, said on Tuesday there was conflicting evidence during the original House of Horrors inquiry as to whether West had carried out renovation work at the cafe in 1968 or later, in 1976.

“Since then there has been a lot of rumour and folklore about Mary and Fred‘s link with the cafe and the decision was made that there was insufficient evidence at the time to excavate the site,” Mr Turner said.

“I met the Bastholm family on Monday and spoke with them at length about what we were going to do and the plan moving forward.

“Clearly since 1968 the family haven’t known what’s happened to Mary.

“There has been some speculation that she may have been linked to Fred West at that time and there was conflicting information within the investigation around that.

“But it is really important to them that we do actually now search for the truth and find out once and for all if Mary is buried under the basement.”

On Friday 7 May officers were called to a café in Southgate Street by a production company filming a documentary. They reported that they had found possible evidence to suggest a body could be buried within the property.

Detectives attended and the Major Crime Investigation Team deemed that further assessments were required in order to determine whether an excavation was necessary. This was in the context of past links between the building and the disappearance of Mary Bastholm.

On Wednesday 12 May, police announced a plan to continue forensic assessments, before a more considered decision around the extent of excavation could be made.

On Monday 17 May, the detective leading the investigation at the Clean Plate café said that excavation work could now take place following assessments at the scene.

One of the findings presented to police was a photo taken by the production company of what appeared to be blue material buried in one area of the cellar.

Since the production company contacted officers, Gloucestershire Constabulary assessed the information with specialists carrying out a series of examinations in the café’s cellar.

Forensic archaeologists on Monday confirmed that there are a number of structural anomalies within the cellar that warrant further exploration.

On Tuesday 18 May, police were seen removing objects from the cafe prior to excavating work. Officers were seen carrying a number of items including wooden doors. There has been no official statement on what exactly was removed.

On Wednesday 19 May (today), excavations began.

Uniformed police officers have arrived at the cafe in Gloucester which is at the centre of the latest police investigation, according to our reporter who is outside the premises.

Photos show a number of officers entering the white tent erected at the front of the building, and an officer guarding the rear of the property.

Loud intermittent drilling can be heard from the street outside and a bouquet of flowers has been left at the scene.

The family of Mary Bastholm, who disappeared in 1968 aged 15, have issued a statement on the latest investigation in Gloucester, saying they hoped it would provide “closure”.

“We are extremely happy Gloucestershire Police is continuing to try and search for Mary and this gives us a chance to potentially put her at rest after all these years,” the family said.

“We hope this is a chance to finally get closure for Mary and would like to continue to ask for privacy whilst the excavation is ongoing.”

Ex-Rose West lawyer Leo Goatley has suggested police could have used her young age in 1968 as mitigation but had missed their opportunity to get her to talk about Mary Bastholm’s disappearance.

“I don’t think Rose West is going to say anything,” he told The Independent. “My view is if she was involved – and I believe she was involved in Mary Bastholm’s disappearance – she would have been groomed by Fred.

“She would have been just 14 years old when Mary Bastholm disappeared.

“I think the opportunity is probably lost now, but it could’ve been explained to Rose that her involvement in that would have been almost as a victim, as an involuntary instrument of Fred West.

“Clearly that kind of explanation cannot possibly hold with later killings but I think that it would’ve been a mitigation, it might have even been some sympathy.”

The Nelson Trust, the charity which runs The Clean Plate cafe which is the focus of today’s excavation work, has declined to comment on the latest efforts to dig into voids found beneath the property.

Forensic archaeologists have confirmed that there are a number of structural anomalies within the cellar that warrant further exploration and six voids in the floor will be examined.

Detective Chief Inspector John Turner, who is leading the investigation, said Fred West was a regular at the cafe – then called the Pop-In – and knew Mary West as she worked there as a waitress.

In a statement to the media last week, the trust said: “Our thoughts and sympathies are very much with the families affected by this long running, tragic story.

“As soon as we were made aware of the situation, we have done everything we can to accommodate the investigation. The Clean Plate will remain closed until all necessary activity is complete.

“It is an extraordinary twist of fate that this building, now associated with a story as tragic as that of the victims of Fred and Rosemary West, is part of a charity working to support women at risk from violence.

“At The Nelson Trust, we work hard to support women who have experienced violence so they can have a life of security, away from the stress and trauma that violence causes to its victims and survivors.

“From our Women’s Centre in Gloucester, we support women who experience multiple and complex needs, the women and girls who sadly, are often most vulnerable to experiencing sexual and other forms of violence.”

Rose West’s former lawyer Leo Goatley, who represented her between 1992 and 2004, said he would be surprised if the “voids” discovered in the cellar of The Clean Plate cafe were linked to serial killer Fred West.

He told The Independent: “I hope they do find something but I think the fact [they’ve found] six voids I think that’s incidental, I’m sure that’s some sort of architectural remnant.

“I’d be really surprised if it had anything to do with Fred West’s handiwork.

“That’s not to say he didn’t leave something if he did do work there, but I think the timeline for him working there is highly speculative and I’m not convinced it dovetails with the disappearance of Mary Bastholm.”

He said there could be “many other explanations” for the voids found in the cellar of the cafe missing teenager Mary Bastholm once worked at since there are Roman ruins in Gloucester.

But he admitted the fact the piece of material found at the location was blue – the same colour as the clothing the 15-year-old was wearing when she disappeared – was “a good start”.

Mr Goatley added that he hoped Mary’s family could get “some sort of comfort” if any remains are uncovered at the property.

He said: “I think it would provide closure, that word gets bandied around, it would provide some sort of answer that may afford some sort of comfort.

“I think knowing is better than not knowing.”

Contractors have been seen entering the cafe with digging equipment, (see 10am post).

Pneumatic drills, shovels and thick black bags were taken into the cafe on Wednesday morning as the investigation gathers pace.

The former lawyer for Rose West, who along with her husband Fred tortured, raped and murdered an unknown number of women over a 20-year period, has said his former client is unlikely to cooperate with investigators searching for the body of missing teenager Mary Bastholm.

Speaking to Sky News, Leo Goatley said: “I don’t think it’ll get anywhere unless she’s had a great shift in mindset, she’s put this great wall up and she won’t want to visit horrors of her past.”