More teams could be thrown out of European competitions next season after Uefa informed clubs it would continue its hard-line position on multi-club ownership. It follows Crystal Palace's controversial demotion from the Europa League to the Conference League this season.

Uefa issued a circular on Monday to underline that 1 March is the strict deadline for compliance. It insisted there would be no extension to get around the regulations after this date. There had been speculation that the rules could be relaxed. But emboldened by the Court of Arbitration for Sport's (CAS) detailed ruling, external on Palace's failed appeal, Uefa has instead reiterated that there will be no special dispensation.

Uefa does not permit two clubs within an ownership group to play in the same European competition. The club which finished lower in their domestic league must lose their place if there is a conflict. Before last season this appeared to be a hollow threat as no team had ever been impacted. But concerned that the spread of multi-club ownership was presenting a threat to the integrity of European competition, Uefa's Club Financial Control Body changed the rules.

It brought forward the assessment date from 1 June to 1 March. As a result, three clubs were either demoted or removed in the summer. Palace were the highest-profile casualty. It was ruled that former co-owner John Textor had decisive influence in both the Eagles and Ligue 1 club Lyon, who had also qualified for the Europa League. League of Ireland side Drogheda United and Slovak club FC DAC 1904 lost their places in the Conference League.

All three clubs failed in appeals to CAS, which last week published its full decision in Palace's case. Its judgement backed Uefa's assertion that there was no mechanism for clubs to become compliant after the deadline. On that basis, Uefa has now reaffirmed that the 1 March assessment date "is the deadline by which clubs must comply with the multi-club ownership criteria" and that the CAS ruling was binding for "a strict deadline for compliance".

Uefa added it was "deemed necessary to provide clarity and predictability to clubs ahead of next season and to enable them to prepare ahead of time". In their appeal, Palace claimed that other clubs had been given preferential treatment to modify their ownership structures for admission to Europe after 1 March. Palace highlighted the case of Nottingham Forest.

Owner Evangelos Marinakis had diluted his control of the club in preparation for Champions League qualification for both Forest and Olympiakos. In a similar situation, Chelsea owners BlueCo had issued millions of new shares in Strasbourg in case both clubs ended up in the same competition. Palace claimed this was proof that some clubs had been given extra time by Uefa to sort out their structures.

This was thrown out by CAS, stating that there was no clause in Uefa's regulations that permitted it. It was not tested though, because these clubs did not end up in the same competition. If so, it would have presented an even bigger test of the regulations. It makes Uefa's communication with clubs this week all the more important because it appears to completely close off any loophole beyond 1 March. Clubs in a multi-club ownership structure who think there is any chance of being in Europe must take the necessary steps to be compliant before this date.

If they have not, Uefa will be back next summer to take action again. This could impact clubs such as Manchester United and Nice, who are in the same ownership structure.