Prune early summer flowering shrubs once they've finished their display to keep them young and vigorous and guarantee a fantastic show of flowers this time next year. Deutzia, scented Philadelphus (mock orange), Kerria and Weigela can all be thinned out now.
Remove about a quarter to a third of the very oldest branches, cutting them out cleanly with sharp secateurs as close as possible to ground level. While you're at it, look out for branches which are dead, damaged or diseased and remove those, too. You're aiming to create an open 'goblet' shape of well-spaced branches which allows plenty of air to circulate, minimising the build-up of fungal diseases which thrive in still, humid air.
You may need a toothed pruning saw for the thickest branches: these cut on the pull, so are perfect for working in among thickets of branches. You'll find all the top brands in stock in our garden centre here in Lymington.
Treat yourself to a good sharp pair of secateurs as well, and dead-heading becomes a kind of summer pruning: use your secateurs to snip out spent flowerheads down to the next pair of leaves, and you'll encourage lots of new growth and perhaps even a second flush of colour later in the season.