July 2 (Reuters) - Britain's Spectris ( SEPJF ) has

accepted an improved takeover offer from U.S. private equity

firm KKR, valuing the scientific instruments maker at

about 4.7 billion pounds ($6.46 billion), including debt, the

companies said on Wednesday.

Spectris ( SEPJF ) said its board has decided to withdraw its

recommendation of Advent's 4.4-billion-pound offer in favour of

the higher bid from KKR.

($1 = 0.7281 pounds)