Hundreds of NHS hospitals are hosting adverts for personal injury lawyers, marketing agencies have told the BBC.
The companies, which place the adverts on patient advice leaflets, say NHS trusts are paid up to £200,000 a year, with some using the money to cover staff overtime and buy heart monitors.
Some hospitals are also given gifts of items like uniforms and tea trolleys.
The Department of Health says it discourages the adverts but it is ultimately for trusts to decide.
Legal claims against NHS clinical services rose last year by 27% to £1.48bn.
Blackpool-based BOE Publishing and Pro Vision Systems, in Lytham St Annes, are two of the leading providers of NHS patient advice cards.
The companies have contracts with hospital trusts across the UK - including in Blackpool - to provide racks of cards in accident and emergency wards, giving information on problems such as head injuries and nose bleeds.
The front of the cards are branded with the logos of the NHS and the local trust and the reverse show adverts, most commonly for personal injury lawyers.
One senior NHS manager described the leaflets as "ethically, not ideal," adding: "You know we're not the only ones doing this."
Pro Vision Systems has told You and Yours it has over 200 NHS contracts to supply and maintain the A&E unit racks.
BOE Publishing claims to be contracted to 129 sites in addition to other NHS supply agreements.
The BBC asked several NHS Trusts if they had contracts for personal injury advertising. The majority declined to comment.
Blackpool hospitals NHS Trust confirmed it had an active contract.
University Hospitals of Morecambe Bay NHS Foundation Trust told the BBC it had ended its contract but the BBC found that leaflets bearing legal adverts had not been removed from Lancaster Royal Infirmary.
Some visitors to the hospital described the leaflets as "misleading."
Pro Vision Systems says its "royalty" payments to NHS trusts vary from a few thousand pounds per annum up to £200,000, with contracts lasting an average of eight years.
"The only advertisers who will spend the money required to fund this free service are personal injury lawyers," Pro Vision told You and Yours.
"Certain hospital A&E departments, especially around the North and Midlands, can generate very large numbers of claims.
"Companies have been played off against each other not just to provide the best advice cards and service, but to create income for the trusts."
The company says some hospitals are increasingly reliant on the extra revenue.
"We know two trusts have used this money to pay months of overdue overtime.
"In one case, an A&E department which only had three heart monitors used the money we provided to buy eight new ones."
BOE Systems offers cash and equipment donations to many of the hospitals it supplies.
Recent gifts include "scrubs" uniforms and catering trolleys.
With total payouts for clinical claims hitting £1.48bn in 2015-16, legal firms' costs have also risen to an average 55% of the total claim value, where damages are below £100,000.
However, both BOE Publishing and Pro Vision Systems have defended the record of the no win, no fee industry.
The companies say their contracts prevent lawyers from suing the hospitals in which they advertise.
They also point to the NHS Injury Costs Recovery scheme, which aims to claw back the cost of NHS treatment where personal injury compensation is paid.
Between 2015-16 the scheme collected £197m from third party insurers.
BOE Publishing, in particular, also sees trouble ahead for the industry, due to the government's continued crackdown on small claims injuries such as whiplash.
"Due to the government's decimation of the field of personal injury law we expect the proportion of legal firms in our adverts to drop over the next 1-2 years to less than 25%."
In 2012 the former Chief Executive of NHS England, Sir David Nicholson, wrote to NHS trust leaders warning that legal adverts in hospitals could "undermine the relationship between NHS staff and their patients and therefore should not be supported".
Department of Health guidelines state: "NHS bodies should not consider advertising personal injury or claims management services."
"However, this form of advertising is a matter for individual trusts."
Commons Health Select Committee Chair Dr Sarah Wollaston takes a tougher line.
"I think people will be surprised about this considering the costs of NHS litigation," she said.
"This process is encouraging people to make a claim they they might not otherwise have done."
Both NHS England and the Association of Personal Injury Lawyers declined to comment.
A Welsh Government spokesperson said: "We believe this is inappropriate and encourages an unhelpful 'compensation culture'.
"In 2009 we wrote to all health bodies setting out our expectation that this practice should stop."
The Scottish Government told the BBC: "Advertising is broadly a matter for individual health boards, however we advise to ensure there is no conflict of interest."
A spokesperson for the Department of Health in Northern Ireland said: "There is no policy in place for this particular issue."
You and Yours is on BBC Radio 4 weekdays 12:15-13:00 GMT. Listen online or download the programme podcast.