London Welsh claim they were misled by rugby’s governing bodies into believing plans to play at Oxford United’s Kassam Stadium would be approved, so enabling them to take their place in the top-flight next season.

The Championship club take a 16-point advantage into tonight’s second-leg play-off final against Cornish Pirates following last Wednesday’s 37-21 first-leg victory but a cloud hangs over the club after a Rugby Football Union panel ruled they had failed to meet the minimum standards for promotion.

The RFU argued that because London Welsh did not have “primacy of tenure” at the Kassam they did not fulfil entry criterion, despite founder members London Wasps, London Irish, Sale Sharks and Saracens all playing at football stadiums where they do not control the fixture list, having been granted exemptions from the rule by the RFU.

The announcement has been widely condemned in rugby circles, one online poll suggesting 87.5 per cent of fans believe the ruling unjust. To rub salt into their wounds, the Exiles were informed just five hours before kick-off against the Pirates last week.

Welsh, who have played at Old Deer Park in Richmond since 1957, will appeal, having been offered the pro-bono services of three Queen’s Counsellors but, as of last night, had not received a clear explanation of the decision.

“We are still, believe it or not, waiting for clarification on the ruling,” said managing director and former British and Irish Lion John Taylor.

“There will be a meeting in the next 24 hours which will give us that clarification. Then we will decide our course of action. It is not a question of whether we appeal, because we definitely will, it is more to do with what grounds we will appeal on.

“Because we had been led to believe what they really meant by primacy of tenure we were okay with it. I had meetings with the RFU and Premier Rugby Limited, who run the Premiership, where they stressed primacy of tenure didn’t mean you had to be a tenant.

“What they meant was that the integrity of the competition was protected because you had arrangements in place that basically meant you could play games when they (PRL) wanted them to be played. Their big fear is that you are totally a puppet of a football club.

“But there is huge experience now with Wasps, Saracens, London Irish and Sale and it has always worked extremely well. We have had a lot of dialogue over the past two or three months and we were led to believe that we were moving this towards a satisfactory conclusion for all concerned.

“The RFU have made a rod for their own backs. Because by granting exemptions to all and sundry for not satisfying minimum standards criteria, which they have done with all these founder members but then saying they will not apply to any newcomers, it’s a very tough case for them to make.

“We want to go up and last week’s result showed what we’re capable of.”

Taylor claims the matter is complicated further by the fact that an independent appeal panel would be appointed by RFU disciplinary manager Bruce Reece-Russell. “We’ll be fighting tooth and nail,” Taylor added. “The problem with an RFU appeal procedure is that while it is meant to be an independent panel, it is an RFU panel. We have got some fairly heavyweight legal hitters who will look at all of our options. We think we’ve got a very strong case.

“The irony is the Kassam is terrific. It’s a damn sight better than half the grounds Premiership clubs play in.”

Taylor is also concerned that, with Newcastle set to be relegated if Welsh do successfully appeal, a desire to keep the Premiership’s geographical spread as wide as possible has played a part in the decision to deny them access.

“I am sure there is a bit of a feeling of foreboding within the RFU that if Newcastle go down there is no Premiership rugby north of Manchester, which leaves a bit of a desert up there,” Taylor said.

In the short-term, Welsh’s players must concentrate on finishing off the job on the field in order to ensure their fight can continue off it.

Jon Mills, who heard about last week’s decision in the team hotel from a friend who had been watching Sky Sports News, will captain the side from blind-side flanker.

The 28-year-old said: “We have to take care of what we can do on the pitch and worry about the whole promotion scandal after that.”

Both the RFU and PRL both declined to comment.

The football stadia in rugby

London Welsh (Kassam Stadium, capacity: 12,500)

The building of Oxford United’s home was beset with financial difficulties. West end still undeveloped but stadium has good transport links.

London Wasps (Adams Park, capacity: 10,300)

Club are desperate to move away but the council’s failure to grant planning permission for a new stadium has seen Steve Hayes put Wasps up for sale.

London Irish (Madejski Stadium, capacity: 24,200)

Excellent modern stadium. However, the capacity is more than double the Exiles average so ground lacks atmosphere.

Sale Sharks (Edgeley Park, moving to Salford Stadium, capacity: 10,900)

Sale have played at Stockport’s ground for nine years but will move to Salford next season. Edgeley Park has been unpopular with Sale diehards.

Saracens (Vicarage Road, moving to Copthall, capacity: 19,900)

One of top-flight’s least loved grounds. One stand is only open to the media. Sarries intend to move to redeveloped Copthall next season.