An underwater search for missing Nicola Bulley is continuing following a fresh appeal by her partner, who said her two daughters “desperately” miss her and “need her back”.

The search for Ms Bulley, 45, is entering its 11th day after she went missing on January 27 in St Michael’s on Wyre, Lancashire.

In a statement released on Monday through Lancashire Police, her partner Paul Ansell said: “I have two little girls who miss their mummy desperately and who need her back.”

Later on Monday night, the head of a team of private underwater search experts cast doubt on the force’s current working hypothesis that Ms Bulley had fallen into the river.

Ahead of the Specialist Group International (SGI) beginning its second day of searching the River Wyre on Tuesday, Peter Faulding said he did not think the missing mother was in the water.

Speaking with TalkTV, Mr Faulding – a leading forensic search expert and SIG’s founder – said: “I personally don’t think she’s in the river, that’s just my gut instinct at this point.”

He added that his team of divers would go back up the river on Tuesday, to search once again near the point where Ms Bulley’s mobile phone was found on a bench.

In a separate media interview on Monday night, Mr Faulding admitted he was “baffled” by the case.

“Police were there on day one diving where the phone was found on the bench,” he told the Daily Mail.

“Normally, if a person has drowned, they go down within a few metres if being searched for the same day.

“In another couple of days I will be confident she is not in that area at all. We have the best sonar you can buy. We have scanned a huge area today (Monday) and there is nothing there.”

The expert diver added: “A body will move after a time, but they searched that area and came up with nothing – that is what is weird here. We are baffled.”

The group, which is based in Dorking, Surrey, and has been volunteering its services free of charge, has been using specialist sonar equipment to look for Ms Bulley in the River Wyre.

After spending Monday searching “three or four miles” of the river until it grew dark alongside Lancashire Police, Mr Faulding told the PA news agency: “It’s a negative search, no signs of Nicola”.

He added that his team will look through another stretch of river on Tuesday “towards where Nicola went originally missing”.

Mr Ansell, her partner, meanwhile said in his statement: “This has been such a tough time for the girls especially but also for me and all of Nicola’s family and friends, as well as the wider community and I want to thank them for their love and support.

“We are also really grateful to Peter and his team from SGI for coming up and helping support the work of Lancashire Police as they continue their investigation.”

The force has searched the river and riverbank all the way to the sea, using search teams, sonar, search dogs, drone, helicopter and CCTV.

On Monday, Lancashire Police released two new images of Ms Bulley on the day she went missing, when she dropped her two daughters, aged six and nine, off at school and then went on her usual dog walk alongside the river.

Her phone, still connected to a Teams call for her job as a mortgage adviser, was found on a bench on a steep riverbank overlooking the water, along with the dog lead, with the dog harness on the ground.

“Our working hypothesis remains that Nicola sadly fell into the river for some reason, but we remain open minded, and we are continuing to carry out a huge number of inquiries,” the force said.

The force is confident, after reviewing CCTV, that Ms Bulley did not leave the field near the river via Rowanwater – either through the site itself or the piece of land at the side – and she did not return from the fields along Allotment Lane or via the path at the rear of the Grapes pub onto Garstang Road.

Officers are now focusing on the river path leading from the fields back to Garstang Road, and urged drivers and cyclists who travelled that way on January 27, as well as anyone with CCTV or Ring Doorbell footage, to contact them.