Bullock ran away from the rest of the field to win in 46.13 seconds, a personal best. His reward could be a place in Britain's 400m relay squad for the World Championships later this month.
Bullock, at 17 the youngest man in the team, is the fifth successive Briton to win this event and follows in the footsteps of the likes of Roger Black and David Grindley.
Coming off the last bend Bullock was so far ahead of Sweden's Rikar Rasmusson he was able to practically walk the home straight. The continued looks over his shoulder probably cost him first sub-46 time of his career, but he did not care. 'My main aim was to win because I felt a lot of pressure beforehand,' he said.
Chris Butler, Bullock's coach, believes he has the talent to be better than Grindley, the UK 400m record holder who he also advises. 'Guy's got more ability, and the potential to go just as far, if not further,' Butler said.
Bullock is the third European Junior champion Butler has coached, following in the footsteps of Grindley and Craig Winrow, winner of the 800 metres in 1989. Much of Butler's work is also with Wigan's rugby league club, where he is the sprints coach.
Merry first represented Britain in these championships as a 15- year-old in 1989, but this was her first international title after coming so close on many occasions. 'At long last,' she said, after beating Hana Benesova, of the Czech Republic, who had pipped her to the 100m final on Friday.
Once she got into her running after uncoiling her long legs, Merry was never going to be caught as she clocked 23.35, with Hallamshire's Sophie Smith finishing third in 23.63.
Howard's victory was as unexpected as it was emphatic. He killed the competition stone dead in the first round with a leap of 7.76 metres. No one else was able to get without 15 metres of the Oxford athlete.
British long-jumping has been down in the dumps since Lynne Davies retired two decades ago but Howard hints at better times around the corner. In the third round he had a huge no jump that looked to be over eight metres, unknown territory for British jumpers these days.
To round off a heartening day, Medway's Kirsty Morrison was second in the javelin with a throw of 55.82m and Crawley's Larry Achike third in the triple jump with 16.31m.Reuse content