Katie Boulter lost to Belgium's eventual champion Belgian Yanina Wickmayer in the Surbiton Trophy semi-finals last weekKatie Boulter has replaced Emma Raducanu as the British number one women's player following her run to the Surbiton Trophy semi-finals.
Boulter, 26, will hold the top spot for the first time in her career when she plays at the Nottingham Open this week.
Raducanu, 20, became British number one after her US Open triumph in 2021 but has been hampered by injuries since.
"Naturally, I am very proud to join the women before me who have reached that historic spot," Boulter said.
"However, my main goal remains on improving my ranking and continuing to work hard.
"It's going to be an exciting summer as we are all very close in the rankings."
Ranked 126 in the world following her three victories at Surbiton, Boulter is two places and 19 points above Raducanu in the latest standings, with Jodie Burrage (131), Katie Swan (134) and Harriet Dart (143) all close behind.
Raducanu is set to miss the summer season - including Wimbledon - after undergoing hand and ankle surgery, which also kept her out of the French Open.
At Wimbledon last year, Boulter recorded the biggest win of her career in beating former world number one and 2021 runner-up Karolina Pliskova to reach the third round of a Grand Slam for the first time.
Leicester-born Boulter first picked up a racquet at the age of five before going on to represent Great Britain at eight.
Her breakthrough year came in 2018, when she won her first ITF 25k and 60k titles, before reaching her first WTA quarter-final at the Nottingham Open as a wildcard.
She reached a career-high ranking of 82 in 2019, however a stress fracture of the back kept her out for six months and disrupted her progress.
Boulter has been drawn against compatriot Emily Appleton in her first match in Nottingham on Tuesday, with coverage of this week's tournament available on BBC iPlayer, the BBC Sport website and app and the BBC Red Button every day.
