So, you've followed the Gentoo Linux Localization Guide and the the NTP guide on the wiki...

cp /usr/share/zoneinfo/Europe/London /etc/localtime

In /etc/conf.d/clock:

TIMEZONE="Europe/London"

In /etc/conf.d/clock:

CLOCK="UTC"
CLOCK_SYSTOHC="yes"

In /etc/ntp.conf:

# Some UK based stratum 2 servers
server ntp2b.mcc.ac.uk iburst
server ntp2c.mcc.ac.uk iburst
server ntp2d.mcc.ac.uk iburst
server ntp.cis.strath.ac.uk iburst

/etc/init.d/ntpd restart

...but the time is still not adjusted for daylight savings. Perhaps you're getting an error like this in /var/log/messages:

time correction of -3501 seconds exceeds sanity limit (1000); set clock manually to the correct UTC time.

The (blindingly obvious) solution... Set the clock manually to the correct UTC time!

ntpdate pool.ntp.org
/etc/init.d/ntpd restart