A border security force being unveiled by ministers today is unable to search for illegal immigrants at weekends because of a £100million budget crisis. The UK Border Agency will start life without Customs and Immigration Service staff being trained to share each other’s powers and with only limited rights of arrest.

The 25,000- strong force does not even have its own promised uniform as officials wrangle over the design. One immigration source said: “Basically, it is going to exist in name only at the outset.