Bruce Buck has warned clubs across Europe that they cannot hope to replicate the rise of Chelsea and Manchester City in the past 15 years and instead should “seek their natural position in the football order”.

Chelsea and Manchester City both catapulted themselves into the upper echelons of the Premier League and European football after being taken over by some of the world’s richest men and organisations, first when Roman Abramovich bought the Blues in 2003 and then when the Abu Dhabi United Group invested at the Etihad five years later.

Partly inspired by the huge spending of both clubs Uefa have pushed for greater sustainability in European football, introducing Financial Fair Play rules in the 2011-12 season designed to ensure clubs do not spend more than they earn in the pursuit of success.

Those regulations have largely been successful in improving the profitability of the sport. However critics claim that it has also made it impossible for those not residing at the continent’s top table to spend their way to a higher level.

Significantly there is a £50million revenue gap between the 12th and 13th most successful clubs in Deloitte’s annual Football Money League and Buck, speaking at the Leaders in Sport Business Summit, suggested the gap may now be too big for any club to bridge.

“There are 10 or 12 big clubs in Europe right now and I think five to 10 years from now in round terms those 10 or 12 clubs will be the big clubs then,” the Chelsea chairman said. “The mix in terms of who’s on top with respect to revenue, performance and trophies, that is up for grabs.

“The dream in England is if you support a Conference team someday you’ll win the Premier League. Financial Fair Play has pluses and minuses. One of the minuses is that dream is not possible. What Chelsea did in 2003, what Man City did five years later, that is virtually impossible under FFP.

“In terms of competitive balance, which is always viewed in a negative way, I personally believe that for the development of football marquee clubs and marquee players are important. It’s important in developing fanbases, encouraging young people to engage in this sport and it’s also important in terms of the large clubs having the ability to put a lot of money into good causes which they do.

“I’m not in favour of dumbing down the large clubs to make all clubs the great unwashed. They’ve done that in the US over the last 20 years and I think it’s been to the detriment particularly of baseball.

“I just don’t think it works for the long-term. Clubs have to seek their natural position in the football order. No matter where you are in that you want to improve but I don’t think we should assume that because every club is not equal that therefore it’s bad.”

Whilst Chelsea speculated to accumulate in the early years of Abramovich’s tenure they have pursued a different model, with their submission to Companies House in January 2018 revealing a drop in wages and near £70million profit in player trading in the previous years.

Indeed since 2010 the Blues have made a profit of roughly £200m in the transfer market.

Discussing Chelsea’s drive towards sustainability Buck said: “It is developing, I think that we are all looking to be break even and even be profitable over the long term but it is difficult.

“The reason you have a football team is to win trophies, although there’s not a direct correlation, winning trophies requires a lot of investment.

“At Chelsea we have worked very hard to push the sponsorship model. We have done everything we can to increase our match day revenues and non-match day revenues at events like this. Most importantly, and we are at a crossroads, we are looking at media and broadcasting.

“We are looking at the opportunities for the future to really make this club stable and profitable for the long-term.”

Buck has been chairman at Chelsea since Abramovich bought the club and noted that he viewed both himself and the Russian billionaires as mere “caretakers” of a club that practically belongs to its supporters.

“I remember some years ago I was meeting with a large group of fans and made the horrible mistake of saying the company rather than the club,” he said. "The fans started gagging and I learnt early on that, notwithstanding the fact that Roman Abramovich is the owner of our club legally, the fans view him as just taking care of the club for a certain period of time.

“He’s the current caretaker but the club is theirs. Legally that’s not correct but as a practical matter it probably is correct.

“As we try to develop our fanbase abroad we always keep in mind our fanbase here. The fact that they’re screaming and yelling in the stadium is part and parcel of what helps develop our fanbase overseas.”