In London, John Coffey, 52, and Bernardo Marti, 48, exchanged vows as the clock struck midnight, before being pronounced "husband and husband".
They were among several couples bidding to be first to take advantage of last year's Marriage (Same Sex Couples) Act.
In Brighton on England's south coast, Neil Allard and Andrew Wale(photo) exchanged vows and rings in the opulent splendour of the Royal Pavilion in front of about 100 guests.
Wearing velvet-collared three-piece suits with white flowers in their buttonholes, the smiling couple of seven years hugged and kissed after sealing their marriage.

Source: Agencies