British football clubs will be on high alert over Easter after the attack on the Borussia Dortmund team bus, warned a security expert.
He says Premier League clubs - such as Manchester United who host Chelsea this weekend - will be upping protection at stadia, training grounds and even hotels where players and staff stay after the audacious "Islamist" strike in the "heart of Europe."
Police are investigating a possible Islamic extremist link to the bombing of the Dortmund team bus, according to the German media..
Security expert Will Geddes said the bomb blasts as the German team was driven to its Champions League home quarter-final will have a bigger impact on football than when terrorists attacked the Sri Lankan cricket team in Pakistan eight years ago.
Mr Geddes, who runs the International Corporate Protection agency, said: "This was an attack on football carried out in the heart of Europe.
"That is not to say cricket hasn't got its followers - it's also massive, but football is at a whole new level - and will send alarm bells ringing throughout the English game and leagues around the world.
"At first I was sceptical about it being ISIS. I thought they would be more likely to strike inside or outside a stadium - like we saw in Paris.
"An attack on a multi-national German club team on their way to a game comes as a real surprise - and really does show nowhere is completely safe for players, fans or staff.
"This includes training grounds, hotels and even the routes players take to a match now."
Asked if the incident will worry football fans in Britain attending dozens of games over the Christian Easter holiday weekend, he said: "It will and it won't.
"I don't think fans are going to be put off going - but it would be a surprise if it's not in their mind.
"I know Premier League teams are working with security experts to increase protection at their stadiums. You can never say anywhere is 100 per cent safe - but I can assure all the fans they are doing all they can to get as close to that as possible."
Mr Geddes said it was much too early to say if those behind the attack were home grown terrorists or this was another case involving illegal immigrants - like we saw in Stockholm on Friday.
He said: "It really is too early to say - and I wouldn't even like to hazard a guess. It certainly wouldn't be helpful."
But the actual devices themselves could help them to track down those who were responsible.
He said: "Right now the police will be looking at the devices which can provide a lot of clues.
"We understand they were three pipe bombs hidden in a hedge that were set off by a cellphone.
"Their construction, component parts and the level of expertise with which they were put together may give them a good idea about who was behind it.
"Obviously a lot of planning was involved - including knowing the route from the hotel.
"ISIS is always on the look-out for the easiest targets that will provide the biggest publicity.
"It knows football is the global game - the people's game.
"It's impact will be reverberating around the world - not just Europe."
In March 2009 Islamic terrorists sprayed the Sri Lankan cricket team's bus with bullets and fired a rocket and a grenade as the team travelled to a match against Pakistan.
Seven players were wounded and six police killed before the bus reached the safety of the stadium.
England cricketer Stuart Broad's father Chris - a former Test player and an international referee - was hailed a hero after he laid on top of Ashan Raza to stop the umpire losing blood after being shot twice.