By Gavin Stamp
BBC News business reporter
Pulling off one of the largest and most daring cash robberies of all time is one thing.
Disposing successfully of the loot and enjoying the benefits is another matter.
For the criminals who have made off with more than £20m from the headquarters of Northern Bank in Belfast, the problems may only just be beginning.
Firstly, they will have to contend with the huge worldwide publicity that their heist has generated.
Police in the United Kingdom and across Europe will be hot on their trail while shopkeepers from Ballymena to Brighton will be alert to any large or unusual purchases for the next few weeks.
Secondly, the sheer size of the robbers' hoard could turn out to be a millstone around their necks.
Getting rid of £20m without causing huge suspicion is likely to tax even the most resourceful and determined of criminal minds.
Not only do the stolen notes each have their own serial number, making them easy to identify but the majority are denominated in Northern Ireland currency.
Although this is accepted throughout the United Kingdom, far fewer notes of this type tend to be in circulation outside Northern Ireland, making any effort to disperse them in England more risky.
"They have a massive headache," says John Horan, a money laundering expert with accountants Harbinson Mulholland. "To some extent, they have been the victims of their own success."
Furthermore, the laws governing reporting of suspicious money flows have been tightened up over the past two years, making it far harder for the criminals to discreetly invest their loot in a piece of real estate or an Old Master.
While banks have always had a legal responsibility to report suspicions of potential money laundering, the Proceeds of Crime Act passed in 2003 has extended this obligation to a whole raft of businesses and professionals.
"If they're thinking of buying property, that's a bad idea because property developers, estate agents and conveyancing lawyers are regulated and all have an obligation to report their suspicions," says Mr Horan.
Setting up a front company is the most feasible option
"Thinking of buying a Matisse or a nice Rembrandt? That's a bad idea too because high value dealers such as auction houses are also regulated."
The robbers still have a number of options, money laundering experts agree, although they are limited.
If they plan to keep the money within the United Kingdom without resorting to burying it, setting up a front company is the most likely option.
"They can set up a fake company which can be used to nominally provide services and invoices for those services," says Trevor Mascarenhas, a partner at Phillipsohn Crawfords Berwald, a law firm specialising in fraud and money laundering.
"They can then take the cash and put it through the system, paying tax on what they purport to provide and try to legitimise the money."
To do this successfully, says Mr Horan, they would need the assistance of an expert money launderer who would expect to take a major cut of the proceeds.
More likely, however, is that the robbers will attempt to smuggle the money out of United Kingdom in multiple consignments so as not to jeopardise the entire haul.
Drug laundering organisations in South America and Russian criminal gangs operating across Europe may provide a ready conduit for the money, channelling it through it banks willing not to ask too many questions.
According to Ian Hopkins, a senior consultant with corporate investigators Carratu International, Colombia is one destination the robbers may consider.
"There are places like that which are not too concerned where the money comes from. There are banks which will take their 2% to 3% and deal with the rest of the money."
The money could even ultimately find its way back into the British economy through offshore businesses and accounts.
Whatever the fate of the money, most experts believe the robbers may have taken on more than they can chew.
"I would be very surprised if they expected to steal £20m," says Mr Hopkins. "It is like the Great Train Robbery. They are likely to be surprised and not a little panicked about how much they have got."