The head of the British police contingent at Euro 2012 has urged Ukrainian officers to "make an example" of isolated racist incidents.

Assistant Chief Constable Andy Holt said there was "not much you can do" if large groups of supporters are involved in abusive chants and actions.

But he claimed the arrest of individuals could act as a deterrent to stop the problem becoming widespread.

At an open training session in Krakow, Poland on Wednesday, Dutch players were subjected to monkey chants with Holland captain Mark van Bommel branding the incident "a real disgrace".

If individuals engage in inappropriate disgusting racist behaviour and there are lots of them, the reality is practically there's not much you can do on the day. You might be able to take CCTV footage and decide to prosecute after the event. But if you've got a football stadium with lots and lots of people engaging in criminal behaviour, then it is very difficult in the heat of the moment to try and do something and do it safely and appropriately. One of the things that we've been advising is if you've spotted individuals doing something inappropriate that you tackle that very quickly and swiftly and make an example. If people think, 'oh my goodness, that guy made a chant, made a gesture, threw something - maybe a banana on the pitch or something - and look he's now heading to the cells', in my experience that's always a deterrent. But you need to do that when you can, rather than when there's 3,000 doing it. If our commander spots something that is of concern to him he would raise that with his Ukrainian colleague. But perhaps more importantly he's able to say 'they always sing and chant in that manner and that isn't the precursor to any disorder, it's just them enjoying themselves'. A home nation with lots of home support - and potentially something riding on it - it could be an edgy fixture. There's a whole range of things that could conspire together to make that last game the most difficult of the first three games and we are obviously acutely aware of that.

A total of 18 British officers are deployed in Ukraine and six in Poland - led by the Association of Chief Police Officers - to help up to 8,000 local armed police deal with fans at games.

Around 3,000 England fans are expected to attend the team's opening match against France in the Ukrainian industrial city of Donetsk on Monday night.

The commander of the British officers will be in the police control room during the game to help the local force interpret the behaviour of England fans.

He admitted that the most difficult of England's three group fixtures from a police perspective will be the final game, when they face Ukraine.

England fans will be heavily outnumbered for the match in Donetsk on June 19.