The only candidates who need to take an extended test are those who have previously been disqualified from driving and have been ordered by a court to take an extended test. Only after they have taken this test will they be allowed back on the road—a standard test won’t suffice.
As this test is longer and features more stringent requirements, it places additional demands on the examiner, and thus is more expensive. In fact, extended driving tests are double the price of their standard equivalents. This means that daytime weekday extended tests cost £124, while evening and weekend extended driving test prices stand at £150.