They are just gaming the contingency, not 'planning' for it.
From the Telegraph:
The Treasury is working on contingency plans for the disintegration of the single currency that include capital controls.The preparations are being made only for a worst-case scenario and would run alongside similar limited capital controls across Europe, imposed to reduce the economic fall-out of a break-up and to ease the transition to new currencies.Officials fear that if one member state left the euro, investors in both that country and other vulnerable eurozone nations would transfer their funds to safe havens abroad. Capital flight from weak euro nations to the UK would drive up sterling, dealing a devastating blow to the Government’s plans to rebalance the economy towards exports.Earlier this year, Switzerland was forced to peg its currency to the euro to protect the economy after a massive appreciation in the Swiss franc due to spiralling fears over Europe.
The plans emerged as Spain’s new finance minister Luis de Guindos warned the country’s economy was set for negative growth in the last quarter.
Speaking yesterday he warned the next two months “are not going to be easy”.
Britain’s response to a euro meltdown would reflect measures taken by Argentina when it dropped the dollar peg in 2002 and by Czechoslovakia after the country broke in two in 1993, according to sources. Faced with a massive capital inflow, the Czech Republic temporarily imposed taxes on foreign inflows to banks and capped the amount of overseas credit domestic banks could use....MORE