Prime Minister David Cameron also confirmed plans for a special service for those caught up in the Tunisian atrocity to be held in the autumn.

The announcements come as the country today remembers the 52 victims, and hundreds of survivors, of the 7/7 London bombings.

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Prime Minister David Cameron said: “Those who lost their lives in Tunisia last week were innocent victims of a brutal terrorist atrocity. It is right that we mark and commemorate them and others murdered by terrorists overseas, appropriately and support the loved ones they have left behind in every way we can.”

George Osborne decided that good causes should benefit from the misdemeanours of bankers, and that penalties levied by the Financial Conduct Authority should be reserved for such a purpose. More details will be announced the Budget tomorrow.

Foreign Office minister Tobias Ellwood, whose brother Jonathan was killed in the Bali bombing of 2002, said: “Having been through a similar situation, I know how important it is that these families, who have been united by a single tragedy, have that marked in one place.

“They will end up providing mutual support to each other, and to have this memorial to their loved ones will be very important. It is also right that the nation recognises the scale of this appalling event.”

Mr Ellwood, who has led a long campaign for a single memorial to all victims of terrorism overseas, said he was delighted this would also go ahead.

He said: “Sadly, we live in very difficult and dangerous times. We have to recognise that there are many victims of terrorism who do not have a grave, whose families don’t have a place where they can lay flowers and grieve in the normal way.

“It is therefore appropriate that we have a national memorial for those caught up in terrorism abroad. These people must never be forgotten.”