John Guidi pitched a tent outside the head office of CYBG, the owners of Clydesdale Bank, in Glasgow city centre on Sunday and has refused to eat since.
The 63-year-old, from Bothwell, South Lanarkshire, is protesting against Clydesdale and its handling of business loan repayments.
With financial backing from the bank, Mr Guidi built a portfolio of 150 residential properties in and around Glasgow.
The loans were transferred to National Australia Bank and subsequently sold off to New York-based Cerebrus in 2014.
The following year Mr Guidi’s businesses were put into receivership by Promontoria Chestnut, a debt collecting agency linked to Cerebrus.
An on-going legal battle followed. Mr Guidi claims he is now weeks away from losing the family home he has lived in for the past 30 years.
CYBG said its decisions have been externally reviewed.
The dispute was raised by Mr Guidi’s MP, Angela Crawley, in an urgent question in the House of Commons on Tuesday.
“I’m 63 and I’m about to lose my house,” Mr Guidi told The Scotsman. “I’m a desperate man. I’ve been involved in litigation now for several years.
“This seemed like the last option I could take. I’m prepared to stay as long as it takes.
“The reaction from the public has been brilliant. I’ve received messages of support from as far away as Vietnam.”
Asked what it would take to end his protest, he said: “I want the bank to sit down and recognise their fault in the loans they sold me, and subsequently sold on to an American hedge fund.”
Speaking in the Commons, Ms Crawley, SNP MP for Lanark and Hamilton East, said Mr Guidi was only one of several business owners to have become entangled in similar legal disputes with lendors.
The UK Government said it expected high standards across the financial sector.
Ms Crawley told the House: “In 1998 John Guidi built a business in the west of Scotland to a portfolio of almost 150 properties. Clydesdale Bank backed that business from its very beginning. He has told me how he was treated by bank chiefs as a model customer. In only 15 years he built a property business worth £16 million.
“He never missed a payment and was in regular communication with the bank and appeared to have a great relationship with the organisation.
“My constituent has informed me that Clydesdale Bank changed the structure of his loans in 2002 and introduced him to tailored business loans. Mr Guidi informed me that in 2014 Clydesdale Bank sold its tailored business loans to Cerebrus Capital Management, an American private equity business.
“He says they aggressively pursued the debt and subsequently put his company into receivership a few months after purchase.
“As a result of my constituent signing a guarantee he has been made personally bankrupt and the company are pursuing his family home. He only has a few weeks until he is evicted and has taken the decision to start a hunger strike in protest.”
Treasury minister John Glen confirmed that Andrew Bailey of the Financial Conduct Authority (FCA) had spoken to Clydesdale Bank about the case in question.
He added: “The Government has been consistently clear where there has been inappropriate treatment of SMEs by their bank it is vital these businesses can resolve their disputes and obtain fair redress.
“At the Budget last Autumn, the Government set out its support for the FCA’s plans to expand illegibility to complain to the Financial Ombudsman service to small businesses, as well as micro enterprises.
“This will ensure that from April 1 this year, well voter 99 per cent of UK businesses will have access to fast, free and fair dispute resolution.”
A spokeswoman for CYBG told The Scotsman: “We have offered to meet with Mr Guidi to discuss his case.
“We are confident the historic complaints raised by Mr Guidi against the bank have been properly reviewed and our decisions have been subject to external and independent review.”