agree with Bernie - it will be 10amp which indicates the amount of power you can take off. 10amp is a decent supply. It will be 240volt same as at home.
There is a handy article on UK Campsite providing some details on electric hook-up for tents, including wattage and amp use.
Just remember, while 10 amps is a good rating, it will not power normal home appliances like some kettles. Modern domestic kettles are usually 3 or 4 kw.
Would suggest keeping to appliances 2kw or less to provide some margin. For example a 2000 watt or 2kw fan heater would probably be OK providing no other appliances are connected.
Some camping kettles are around 1.5kw (1500 watts) so should be OK too.
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