UEFA communications director William Gaillard said: “We are going to look into it and see whether there is a controlling interest by Mr Abramovich with two teams in the same group.

“We have to find out whether it is a controlling interest or not. We may already have the facts to decide to dismiss it as a problem but it has to be looked into thoroughly.

“If it was found that Mr Abramovich had a controlling interest in CSKA Moscow and Chelsea they could not both take part in the competition. He would have to decide which team took part.

“We have to have this transparency under EU competition laws and we will carry out the necessary checks immediately.”

Abramovich is a close friend of CSKA president Yevgeny Giner and was a guest in his personal VIP box in Moscow on two occasions earlier this year.

Under current regulations, no person is allowed a controlling interest in two clubs playing in the same competition but UEFA will have to decide whether the sponsorship deal counts as any conflict of interest or whether Abramovich has any other interest in CSKA.

Chelsea will also face reigning European champions Porto, the side current manager Jose Mourinho guided to the victory in the Champions League final in May, and Paris St Germain in Group H.

Chelsea chief executive Peter Kenyon dismissed any problem with the CSKA sponsorship deal.

He said: “It was always a possibility we would draw them and Porto – and the only one we are missing is Valencia [Claudio Ranieri’s new side].

“I have spoken to Jose and he regards it as a tough group with strong teams. Nothing can be taken for granted but I’m sure as always he will do his meticulous preparations and that his experience of Europe will be beneficial.

“We have a new squad and a new manager and we feel well-equipped to be embarking on this round.”

The four English sides have all avoided Italian opposition as well as Spanish trio Real Madrid, Barcelona and Valencia.

Arsenal have perhaps the easiest draw of the four English sides with PSV Eindhoven, Panathinaikos and Rosenborg in Group E.

Manchester United’s task also looks straightforward with Fenerbahce, Sparta Prague and Lyon in Group D.

In Group A there will be a tougher proposition for Liverpool to qualify against last season’s beaten finalists Monaco, Spanish semi-finalists Deportivo La Coruna and Greek side Olympiakos.

Arsenal kick off at home to PSV Eindhoven on September 14 on a crest of a wave after breaking Nottingham Forest’s record of 43 league games unbeaten.

Chairman Peter Hill-Wood said: “It is the best football I have seen played in my 50 years going to games, it has been a great thrill and to break the record is a great achievement.

“I believe we are playing as well as any other team in Europe, we aiming to get to the final and win it.

“We have got a good draw with not a lot of travel either. I couldn’t have drawn it better myself.”

Manchester United’s first fixture is away at Lyon on September 15 and they end their group campaign away against Turkish side Fenerbahce – the first team to beat United in Europe at Old Trafford.

United chief executive David Gill said: “It’s an exciting draw and hopefully come the start of the competition we will have all our squad available and have a good Manchester United team in Europe.

“Fenerbahce’s record against us adds to the spice. I don’t think any of those three teams will be easy games for us but that’s the strength of the Champions League.”

There have been security concerns surrounding English sides in Istanbul in previous years but Gill played down any worries.

He added: “We have to approach these situations in a positive manner and endeavour to make sure it is remembered as a great football spectacle.

“UEFA have decided that Istanbul is a suitable place to hold the final so I’m sure it will be suitable for us to play there too in the group stage – and it would be nice to go back there in May of course.”

There is Spanish opposition in the form of Deportivo La Coruna for Liverpool and chief executive Rick Parry said: “It’s hugely important for us to be back in the Champions League and we are delighted to be here.

“There’s a good buzz under our new manager Rafael Benitez. He’s very intelligent, very hard-working, a nice guy, smiles a lot, is very driven, ambitious and a great coach.

“That feeds back through to the squad. He is working in different ways with the players but they are enjoying it and are responding well.

“We are very excited about our new signings and Milan Baros is a huge bonus. With the way he performed in Euro 2004, it’s almost like having a new signing.

“We played Olympiakos recently and have old friends there while the performances of Monaco and Deportivo last season shows how seriously we have to take them.”

Of the British sides, Celtic’s task looks the most arduous in Group F. They will come up against Barcelona – and former striker Henrik Larsson – as well as AC Milan and Ukrainian side Shakhtar Donetsk, one of the best sides in eastern Europe.