Then some critical parts of the system should be reverse-engineered and the migration path to the new platform validated.

In fact, even if the target of the reverse-engineering is to remodel a system, it must also prototype the migration of some key component to the new architecture to check that it is possible.

In the last few years, however, the reverse has taken place: there has been a migration of labour back to the north-eastern coastal areas to well-paid jobs in the North Sea oil industry.