EXHIBIT 4.5 PERSONAL George Battersby Group HR Director Amersham plc 20 February 2003 Dear George I am pleased to confirm that the Remuneration Committee has approved an increase in your salary to L283,250 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 L182,050. I am also pleased to confirm your award of share options today with a nominal value of approximately L550,000. The performance conditions will be similar to those adopted last year. With best wishes. Yours sincerely SIR WILLIAM CASTELL CHIEF EXECUTIVE