An alleged "rogue surgeon" has been suspended by the General Medical Council after it emerged he might have performed "unnecessary or inappropriate" breast operations on more than 1,000 women in Britain.

Ian Stuart Paterson, a breast cancer specialist who worked at NHS and private hospitals in the Midlands from 1994 until last month, is suspected of misdiagnosing at least 450 of the women with breast cancer when they were in fact healthy, and then performing unnecessary "lumpectomy" surgery.

He also performed unconventional "cleavage-sparing" mastectomies on 700 other women, despite the procedure not being sanctioned in the UK. The technique involved leaving breast tissue around the cleavage area for cosmetic reasons but went against national guidelines which state that no excess tissue should be left behind as this could lead to a return of the cancer.

According to Thompsons solicitors, who are representing almost 100 of the affected patients on a "no win, no fee" basis as they launch compensation claims: "Many of the women operated on by Mr Paterson using this controversial technique have had to undergo further surgery to remove the excess tissue and unfortunately some have had their cancer return."

One of Paterson's patients, 57-year-old Gail Boichat from Staffordshire, says she recently discovered that Paterson had misdiagnosed her with breast cancer back in 1995 when he was working at the Good Hope NHS hospital in Sutton Coldfield, West Midlands. He performed a cleavage-sparing mastectomy on her right breast and then prescribed the strong anti-cancer drug tamoxifen , which she claims caused an early menopause.

She was recalled to hospital in February after the GMC launched an investigation into Paterson and says that a doctor looked at her medical notes and told her that there was no evidence she ever had breast cancer. "I felt shock, horror, numbness. The words want to come out but you can't say anything. You can't speak," she said on Wednesday. "For a while I didn't even tell anybody about this. It messes with your emotions. You feel guilty in one respect because people say, oh, I had breast cancer. Now I can't say I had it, but I had a mastectomy. It does mess with your head a bit."

Heart of England NHS hospital trust has since apologised to Boichat for her ordeal. But like many other women, she is launching a compensation claim and wants Paterson to face criminal charges. "Then I may get some closure. He punished me in some way and I think he should be punished," she said.

Paula Gelsthorpe, a 54-year-old dog groomer, only heard 10 days ago that the two lumpectomies Paterson performed on her in 2002 and 2009 were unnecessary. She said she liked the surgeon – "a wonderful man. His bedside manner was second to none. He was very friendly, very welcoming and he gave what I thought was good reassurance." She felt shocked and betrayed at the news. "I have mixed emotions," she said. "I've been under this cloud since 2002 and then to be told these operations were unnecessary, my first thought was, 'thank goodness, I haven't got cancer'. But then the anger and the betrayal caught up as well."

Paterson was suspended by the GMC at a hearing at the end of last month. He is expected to face a full fitness to practise hearing in summer next year. He could also face criminal investigation following allegations he made claims to medical insurers for unnecessary surgeries or surgeries he did not perform.

Two of Paterson's private breast cancer patients have told the Guardian that they have discovered that Paterson "miscoded" their procedures – submitting claims to insurance companies for more expensive procedures than those which he had actually performed.

The GMC has referred the case to West Midlands police, who said they were "working closely with the GMC to assess the allegations and determine whether a criminal investigation is necessary".

A GMC spokesperson said: "Dr Ian Paterson's registration is currently suspended, following an Interim Orders Panel meeting on 29 October 2012. This means the doctor cannot work as we investigate concerns about his fitness to practise."

Paterson was already banned from performing the cleavage-sparing operations at the Heart of England trust after an an investigation by the trust in December 2007.

Afterwards, the Heart of England trust "began a process of identifying patients who may have undergone this procedure". Some 700 of these NHS patients were urgently recalled last summer, for "a review of their treatment and care".

In a statement late on Tuesday, Paterson, who is being represented by the Medical Defence Union said: "I am co-operating fully with the GMC investigation and cannot comment on any of the issues raised because of my duty of patient confidentiality and the ongoing investigation."

In a statement, Paula Naylor, hospital director at Spire Parkway hospital, said: "We have referred this matter to the General Medical Council so they can investigate Mr Paterson's fitness to practise but cannot speculate on the outcome. Clearly we are looking at what we can learn from these events, but our priority right now is to hold consultations with those patients affected and to provide them with accurate information as quickly as possible."

The hospitals where Paterson is known to have practised are: Heartlands hospital, Solihull hospital, Good Hope hospital (all NHS); and Spire Hospital Parkway and Spire Hospital Little Aston, both private establishments.

Kashmir Uppal, national head of clinical negligence for Thompsons solicitors, describes Paterson as a "rogue surgeon". She said she had never heard of such a wide-ranging clinical negligence case in 16 years of specialising in the field. "It's the largest case that I've dealt with, with the number of women involved and the reasons he was doing this, which we just can't establish. Clearly mistakes do happen in any clinical setting – unfortunately a midwife can misread a CTT trace, somebody will misread an X-ray, a GP won't recognise signs of colorectal cancer … This is different."