Redcurrants, and whitecurrants (which are more really-really-pale yellow-pink) are both Ribes rubrum, and are cared for the same way.
They are hardier than blackcurrants and grow better in cold Northern locations. If you are growing on poorer ground on a scale where the plants won't get much help with soil fertility, then they have the edge as well.
They are completely self-fertile, so you only need one plant for a crop. They thrive best in good, well-drained soil with a neutral pH to slightly acidic, where well rotted organic matter holds moisture near the surface. A handful of bonemeal dug into the soil underneath each plant is recommended.
Plants in full sun but protected from drying winds will make the biggest and sweetest fruit. They tolerate the shade of a north facing wall with open sky overhead, where the fruit will ripen later and be tarter.
They can be grown in three main formats: bushes cordons or fans. Plant between November and the beginning of March. Keep the roots damp (in a bag with something wet inside) right until you are planting them. Do not leave them in water as they drown. When you take a currant out of the bag to plant it, cut back any damaged roots.
Bush plant 1.5m apart 1.5m between the rows
Cordons plant 50cm apart 1.5m between the rows
Fans - Plant 2 metres apart
Wet the roots in a bucket of water and put the red or whitecurrant in a hole with plenty of room for its roots and so the plant will end up with the finished soil level at the same point as before lifting (usually seen as a root collar or "high water" mark on the main stem). Replace the soil, and firm it down with the ball of your foot. Water well.
Weed control after planting matters - weeds provide unwanted competition and so affect crop size. A heavy mulch in early spring (straw or other organic matter is good) helps to suppress weeds, is good for moisture retention and eventually rots down and improves the ground. It also helps stop damage to the feeding roots of redcurrants, which are shallow.
All pruning carried out in the first couple of years creates the form of the plant. Most pruning is done in the late winter or early spring when it is not freezing. A bush, grown on a leg which is 10-15cm of bare stem from the ground up, with an open centred, bowl shaped plant is the best form when grown in the open. This is done in the same way as for Gooseberry bushes, with one important difference: where gooseberries are a bit droopy, making it wise sometimes to prune them back to an inward and upward facing bud (unlike with most plants), currants are pruned back to an outward facing bud, which is normal for most plants.
Used for corners and limited spaces, cordons can be single, double or triple stemmed. Support on a wall or wire frame will be required: a good long bamboo cane is enough for single stem cordons.
February Fertilising: You can spread N-P-K fertiliser around your plants in late Februaury as per their instructions, just before their roots begin to wake up, with about 30g per square metre of Sulphate of Potash (Potassium sulphate) added in. This will make a big difference to their productivity and flavour. Mulching is always good too (if you have poor soil and no mulch, spreading sulphate of ammonia around is also good - about 50g per square metre).
Water very well in dry periods until you have finished picking, and use straw mulch to protect from the sun's heat.
Protect your fruit from birds as the fruit start to change colour with a fruit cage or netting over the plant.
Currants are carried in strings 10-20 berries. When really ripe, they are soft and a deep, rich red. Harvest by taking off each string; a strong pair of scissors helps. For jelly, pick them when they are still a little unripe as there is more pectin in the fruit and the jelly sets better. Leave until they are fully ripe for everything else. Red & whitecurrants freeze well.