This is great news, which I just heard and retweated a retweet from the Cathedral :=
Ordinarily, St Paul’s Cathedral is not open to tourists on Sundays,
but next month, the dome will be opened up for dome-only climbs.The interior remains the realm of the worshiper, while tourists
clamber around the outside.The Sunday Dome climb gives access to the Stone and Golden Galleries
only. The Whispering Gallery is not included, lest your whispering
disturb the praying.On each of the five May Sundays, the Dome will be open for climbs from
9:30m to 5:15pm, and admission will be £6. That compares to £18 for
the full tour.This is an ideal chance to get up high and see the sights, without the
full cost of the building inside. However, you can also pop back
during the week if you want and pay £12 for the full tour — and that
then gets you unlimited repeat visits for a year.Incidentally, the Sunday tour might be just a tiny bit better than
just turning up during the week — as the route is different, so you
get an extra 22 steps to climb up. Exciting!The Sunday Dome climb entrance is in the South Churchyard.