Webb, who was a successful junior as Laura Bolton, was a member at Cairndhu Golf Club, near Larne, before moving to England.
She was the first player to have won the three Irish closed titles - girls, women and seniors. Now 53 and a one-handicapper, she has added another championship to her collection with rounds of 71, 72 and 76 for a level par aggregate of 219 over the par-73 Caldy course.
Laura is the first Irish player to win the over-50s British title since Mary McKenna at Aberdovey in in 2001. Webb's total is the lowest this century.
The average level of scoring went up on the final day with the winner's 76 easily her highest of the three rounds. She bogeyed the second on her way to the turn in 37 and when she bogeyed the 10th her lead had been cut to three shots by Julie Brown.
A birdie 4 at the long 12th - her only gain of the round - stablised Laura and she was able to par in until running up a double bogey 7 at the long 18th for 39 home.
Curiously enough, Julie Brown also finished with a 7 when a birdie would have tied her with the winner. Earlier the Trentham player, who also has one of a handicap, had bogeyed the first and birdied the second and reached the turn in 36, one better than Webb. A bogey at the 13th was followed by Brown's best run of the final round - birdies at the 15th and short 17th - before that final-hole double bogey cost her a sub-par round.
Anne Lewis (Royal St David's), the 2013 champion, for the third place Ann held until the last few holes.
Maria had an indifferent outward half of 39 but was three under par for the last seven holes with a grandstand finish of birdies at the 12th, 13th and 16th.
Ann Lewis had scores of 72, 77 and 79. The 15th provided her only birdie in halves of 40-39 today. Ireland's Gertie McMullen, runner-up 12 months ago, had rounds of 79, 77 an d76 for a 232 total and a joint ninth finish.
Finland's Minna Kaarnalahti, joint leader after an opening 71, followed that great start with rounds of 83 and 80 for 234 and a tied 13th finish.
CSS 75 - Round 1 - Wednesday 14 September
CSS 75 - Round 2 - Thursday 15 September
CSS 76 (+1) - Round 3 - Friday 16 September