A superb dressage routine from Pippa Funnell on Primmore's Pride helped put Britain into the overall lead after the second day of the three-day eventing.
Funnell had 31.40 penalties, the second best individual result behind France's Nicolas Touzaint, who posted 29.60.
Another strong display from William Fox-Pitt on Tamarillo, with 38.60 - the sixth best individually - gave Britain a narrow lead over France and Germany.
Leslie Law's score of 43.20, 10th best overall, gave the team an early boost.
Less than two marks separate the top three ahead of the cross-country section, with Britain on 113.2 points, France on 113.4 and Germany on 114.4.
"I was very nervous yesterday and all day today but once I got on Prinmore I felt much happier and relaxed," said Funnell.
"It is a huge relief that it went well."
Mary King and Jeanette Brakewell, who performed their tests on day one, scored 48.00 and 49.80 respectively.
Elsewhere, there was a setback for the Irish team after a disappointing
display from Edmond Gibney.
The 30-year-old, riding Kings Highway, recorded a score of 68.00, which the
team elected to discard leaving Ireland in eighth place overall on a combined score of 170.00.
"I was very disappointed with that," said Gibney.
"The dressage is the worst phase of the competition for us and it didn't go
"He [Kings Highway] is excitable by nature and I just could get him to
concentrate on the test. He just blew up.
"The cross country will definitely be better for us. He is a good jumper and
I would expect us to make it round."