LONDON, July 29 (Reuters) - British mortgage lending surged by a record amount in June as home-buyers rushed to take advantage of a tax break before it was scaled back, Bank of England data showed on Thursday. Mortgage borrowing rose by a net 17.9 billion pounds ($25.0 billion) in June, the biggest increase on record. A Reuters poll of economists had pointed to a net increase of 7.9 billion pounds. ($1 = 0.7163 pounds) (Reporting by William Schomberg, editing by David Milliken) Our Standards: The Thomson Reuters Trust Principles.