A 22-tonne wooden catapult, which is said to be the world's largest, is to be installed at an historic castle and fired daily during the summer.
The catapult will sit beside the River Avon which runs below the castle
The machine will be built in Wiltshire from 28 tonnes of British oak and then transported in 300 pieces to Warwick Castle where it will be reassembled.
It will be capable of sending missiles 25 metres (82ft) into the air and up to 300 metres (328 yards) along.
Eight men are needed to load the replica, which will take 30 minutes.
Catapults were the principal siege weapon of attack from the 13th to the 15th century.
The machine - which would have been used to aim missiles at defensive walls and throw huge projectiles over fortifications - stands 18 metres (59ft) high and is capable of firing up to 150kg (330lb) of ammunition at a time.
It will sit beside the River Avon which runs below the castle.
"These machines are incredible pieces of engineering and it is really something to see them in motion," said medieval weapons expert Dr Peter Vemming who designed it.
Ready in July
"As well as being the biggest in the world, the setting of the Warwick trebuchet makes it doubly unique.
"To witness a full-scale medieval trebuchet in action is incredible in itself.
"To witness a machine of this magnitude in an authentic medieval setting, with the castle as a backdrop, will be very special."
The trebuchet - which would have been dismantled regularly and transported in lengthy convoys of carts to the next siege in medieval times - is due to arrive at the castle in June and be ready for use in July.