There are a great many islands off shore from the mainland of the United Kingdom - some estimates suggest that there are as many as 5000 islands in total but that number is difficult to verify. However there are certainly more than 1000, which is quite amazing in itself! The total number of islands depends on what definition of an island you use. In particular the answer to the question of - what is an island and what is a rock? There are a huge number of rocks around the UK coast but it would be impossible to live on many of them and that may be the limiting factor between and island and a rock. Whatever the total number of islands there are certainly a great many of them - below are details of the main islands and groups of islands around the UK - from north to south.
Shetland Islands - A group of around 90 islands, of which only 15 are inhabited, lying around 100 miles north of the Scottish north east coast.
Fair Isle - Lying midway between Shetland and Orkney islands in splendid isolation. Fair Isle is just 3km wide and 5km wide with a wild craggy coast, some of which rises to 100 meters above the pounding seas. Home to around 70 people and many more sheep and birds.
Orkney Islands - A group of around 70 islands, of which 20 are inhabited. The southernmost point of Orkney is only 10 miles north of the Scottish coast.
Outer Hebrides - Is an archipelago of islands lying around 40 miles off of the coast of Scotland. The group of islands stretches for about 110 miles along the west coast of Scotland. There are seven main islands of which the Isle of Lewis is the largest. There are more than 30 islands in total, many of which are uninhabited. Also known as the Western Isles - a term which may or may not include the Inner Hebrides.
Inner Hebrides - Is a group of islands lying just off of the west coast of Scotland partially between the coast and the Outer Hebrides. The group includes Islay to the south and stretches north to the Isle of Skye and includes the islands of Jura, Mull and Staffa and numerous smaller islands. The is a newly installed bridge to the Isle of Skye from The Kyle of Lochalsh on the Scottish mainland. All other islands are accessed via ferry or aircraft.
Isle of Arran - Arran lies in the Firth of Clyde some 20 miles offshore from Ardrossan and a few miles to the east of the Kintyre peninsular. Nearby are the islands of Bute and Great Cumbrae.
Lindisfarne - Also known as Holy Island (there are several other Holy Islands in the UK), lies just off shore of England's north east coast, near Berwick-upon-Tweed. The island is connected to the mainland by a tidal causeway; there is a castle and priory on the island.
Isle of Man*- Situated in the Irish Sea just about equidistance from Northern Ireland, Scotland and England, around 40 miles offshore. The curiously named island, the Calf of Man, lies just to the south.
Walney Island - Is a long thin crescent of an island lying just offshore from Barrow-in-Furness in Cumbria. Barely a kilometre wide at its widest point the island has several bird sanctuaries on it.
Anglesey - Is a large island lying just offshore from the northwest Welsh coastline. It is connected to Wales by two bridges across the Menai Straits. There are numerous island off of the Anglesey coast - the largest of these is called Holy Island and is connected by a bridge carrying the A55 road, which terminates at the port of Holyhead.
Ramsey, Skomer and Skokholm Islands - These small islands lie within the Pembroke Coast National Park in southwest Wales. Each of these islands is a sanctuary for many varies of seabirds. There are several other, smaller islands in the same area.
Foulness Island - Is a fairly large, flat island at the mouth of the River Crouch in Essex. It was once suggested as a location for a third airport for London.
Canvey Island - Canvey Island is a town and seaside resort lying in the Thames estuary just south of Southend-on-Sea. It is connected to the mainland by a road bridge. Much of the island is below sea level and is protected by a huge sea wall.
Isle of Sheppey - Sheppey also lies in the Thames estuary, this time on the southern bank near Chatham. the island is mostly rural and connected to the mainland by a road bridge.
Lundy Island - Lies some fifteen miles off the Devon coast at Bideford. The island has around twenty residents and three lighthouses to warn shipping using the Bristol channel. The waters around Lundy have been designated a Marine Nature Reserve - the only one in Britain.
Isle of Wight - The Isle of Wight is a large island just south of Southampton - it is home to around 135,000 people and attracts many thousands of visitors every year. The Isle of Wight is a county in its own right and has a distinctive culture as a separate entity to mainland Britain. The island is well known as a sailing centre and stages an annual sailing event at Cowes each year.
Isles of Scilly - There over 100 islands in the group of which only 5 are permanently occupied. The population is around the 1000 mark but increases in summer months when many tourists arrive. The islands are around 28 miles from the tip of Land's End and they represent the southernmost point of the UK. (The channel Islands not being part of the UK)
Channel Islands* - The Channel Islands group consists of Jersey and Guernsey, the two largest islands and the smaller islands of Alderney, Sark and Herm. The main islands are around eighty miles south of the coast of England - they are closer to France in fact.
Rockall - Although not really an island, more a big rock, we thought we should include it here as it is the most far flung part of the UK and deserves a mention. Rockall is located around 230 miles west of North Uist in the Outer Hebrides islands. It's only inhabitants are seabirds and it is claimed by several other countries as well as the UK - it is important as the UK also claim the seabed around the island.
UK 'islands' that are not islands.
Isle of Thanet - is in Kent near Ramsgate - it is a 'near' island formed by the coast and the Great Stour river.
Isle of Purbeck - is located around Swanage in Dorset - formed by the coast and the River Frome.
Isle of Portland - is located in Dorset just south of Weymouth. This is very nearly and island but is connected to the mainland by the huge pebble ridge that is part of Chesil Beach.
Isle of Ely - Near to Ely in Cambridgeshire - nowhere near the sea but this area was more or less an island in times past when it was surrounded by fens (swamp). Now the area is drained and accessible by many roads.
Isle of Dogs - Located in east London, the Isle of Dogs is a peninsular with the River Thames on three sides and the West India Dock on the forth side. Now a part of the Docklands redevelopment area.
*Note: - that the Channel Islands including Jersey, Guernsey, Alderney and Sark and the Isle of Man are not part of the UK. They are self-governing Crown Dependencies. Their coastlines are not coastlines of the United Kingdom but they are part of the Great Britain.