time limit on Guarantee Scheme repayment

Lets say that an institution (or credit union) goes belly-up. The government have guaranteed your deposits but has there been any indication as to how long it would take to pay us these lost deposits? If, we lost our money in a credit union, could it technically be 10 or 20 years before the government pay the guaranteed money?

I remember hearing speculation around the time of the Northern Rock guarantee, that there could be a significant lag in the time when depositors can get their money returned. However, I couldn't possibly imagine this lag being years. I would imagine if there was a time lag, it would be months.

You mentioned Credit Unions there. It would be also interesting to see if a credit union was to need a bail out, would the Government Guarantee be used or would the ILCU's Savings Protection Scheme be used.