EXHIBIT 4.6

PERSONAL

Andrew Carr
President
Amersham Biosciences

20 February 2003

Dear Andrew

I am pleased to confirm that the Remuneration Committee has approved an increase
in your salary to $618,000 per annum with effect from 1 April 2003.
Additionally, in respect of the 2002 Bonus Scheme, the combination of
performance against financial targets and your personal objectives has produced
a bonus of $137,400.

I am also pleased to confirm your award of share options today with a nominal
value of approximately $1,200,000. The performance conditions will be similar to
those adopted last year.

With best wishes.

Yours sincerely

SIR WILLIAM CASTELL
CHIEF EXECUTIVE