Boulter's Lock

Boulter's Lock is a lock and weir on the River Thames in England on the eastern side of Maidenhead, Berkshire. A lock was first built here by the Thames Navigation Commission in 1772. The lock is on the western side of the river between the main (A4094) Maidenhead to Cookham road and Ray Mill Island. The name is also used for the immediate surrounding area.

The weir is some way upstream of the lock, at the northern end of Ray Mill Island. It is one of the most popular whitewater freestyle kayaking areas on the River Thames, as it has had modifications made to it, to allow kayakers to play on it without causing disruption to other river users.


The earliest reference to a flash lock is in the late 16th century, although a mill is known to have existed here in the 14th century. In 1746 it was written that there was no lock downstream of this lock. The 1770 navigation act did not allow the Thames Navigation Commission to build locks below Maidenhead Bridge, so the lock here built in 1772 was the lowest downstream of the eight first built by the Commission. Originally the lock was on the Taplow side and in 1773 an adjacent resident complained of trespass in his woods by the barge-crews who "very much misbehaved themselves by their indecent conversation and horrid oaths and imprecations". It was referred to as "Boltus Lock". A "bolter" was a miller and hence means "miller's lock" and originally referred to the mill at Taplow. It was exceptional that a lock-keeper's house was built in 1774. By 1780 the lock was reported as being in as bad a state as Marlow and in 1795, Phillips Inland Navigation complained of the deep hole and subsequent shoals caused by the force of water.

In 1825 the City of London complained of the condition of the lock and recommended it be rebuilt on the Berkshire side of the river. The new lock opened in 1828 and was known as Ray Mill pound after Ray Mill Island to which it was now adjacent. The lock cut created Boulter's Island.

This area of the river became popular for boating parties in the late 19th century and early 20th century as portrayed in the painting by Edward John Gregory. The lock was a popular place to visit on the Sunday after Royal Ascot when the wealthy and famous passed through the lock, often on their way to Cliveden. In 1899 an iron railing was placed round the lock to keep spectators at bay. In 1909 the Thames Conservancy purchased Ray Mill Island to provide for expansion of the lock and it was rebuilt in 1912.

Congestion at the lock was a serious problem before World War I, and a novel solution was employed to reduce it. A moving ramp, consisting of wooden slats with chocks to prevent rowing boats from rolling over, was constructed to bypass the lock. The ramp was similar to an escalator, and small boats simply rowed towards it, and were carried up to the higher level while the occupants remaining seated in their boat. The boat lift opened in 1909, and was powered by an electric motor. The date of its demise is uncertain, but its location on Ray Mill island can still be visited.

The salmon ladder opened at Boulters Weir on 19 May 2000 by the Duke of Wellington was the last of a series built on the Thames. The last salmon caught previously at the weir was landed in 1821.


Ray Mead road/Lower Cookham road (A4094) runs alongside the lock, and there is a car park with ample parking off the road. There is a track onto the lock island. An hourly bus route to the lock from Maidenhead town centre is run by Courtney Coaches.

Reach above the lock

After the long cut beside the islands the reach opens out at the head of the Jubilee River on the Buckinghamshire bank. This is followed by Bavin's Gulls on Cliveden Deep with the spectacular hanging beech woods on the escarpment above which sits Cliveden, well known for the Cliveden Set and the Profumo Affair. The river then curves round to Formosa Island and the other islands where Cookham Lock is situated.

The Thames Path follows the western Maidenhead bank along the river until it cuts into Cookham, missing the lock.


The weir at Boutler's Lock is a popular kayaking site. A canoe/kayak flume is installed annually on the weir during the summer and there is a permanent fixed ramp in front of the third of the weir's six gates.

Literature and the media

One of the best known works of Edward John Gregory (1850–1909) is his Boulter's Lock|Sunday afternoon. Nicholas Pocock, the marine artist, lived at Ray Lodge and broadcaster Richard Dimbleby had a house on Boulter's Island. The writer John O'Farrell grew up in 'The Weir House' opposite.


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Building Activity

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