Profits made by selling bulk electricity to the Scottish lowlands would be used to fund "the economic development and social improvement of the North of Scotland."

[4] The first two major schemes promoted by the Board had been at Loch Sloy and Tummel-Garry, but both had been the subject of fierce opposition on the grounds of amenity and fishing.

In order to avoid a repetition of such opposition, the Board devised a scheme which would not fulfill the full potential of Glen Affric, but which would be more likely to obtain approval.

The work was carried out by John Cochrane and Sons, and the dam was built in two halves, using an island in the middle of the loch to reduce the volume of material required.

[5] Construction of the smaller structure began in March 1950, but in February 1951 the financial crisis eased, and plans to build the south wing to its original height were drawn up.

Once adequate setting had occurred, the new concrete was bonded to the old by filling the slot with crushed aggregate and grout, and this process was finished in mid 1952.

Loch Beinn a' Mheadhoin is also dammed, with a tunnel taking water to the main power station of Fasnakyle, near Cannich.

[12] Prince Philip accepted an invitation to open the scheme because he wanted to see whether criticism of the Board for wantonly destroying the beauty of the Highlands was justified.

To suggest that this power house [Fasnakyle] alone destroys the beauty of Glen Affric is being as fastidious as the fairy-tale princess who could feel a pea under 15 matresses.

"[13]One extra benefit of the scheme was that large tracts of arable and pasture land beside the River Beauly between Cannich and Aigas were no longer subject to regular flooding.

Negotiations to resolve these issues took a long time, and a private settlement of £100,000 was made to Lord Lovat in respect of damage to fishing rights and spawning grounds.

[12] To the north in Glen Strathfarrar, Loch Monar is dammed, and a 5.6-mile (9 km) tunnel carries water to an underground power station at Deanie.

The Board were always keen to assist engineers and manufacturers in trying out new designs, and this may have been part of the rationale for using a double arched dam.

A large number of strain gauges, resistance thermometers and other instrumentation were built into the dam, to provide scientific data on the stresses within such a structure.

[16] An aqueduct intercepts several streams to the south of the dam, providing additional water which would otherwise discharge into the River Farrar.

[19] An aqueduct intercepts streams to the north of Loch Beannacharan, and additional water is discharged into the main Deanie pipeline.

[17] Further down the glen, the River Farrar is dammed just below Loch Beannacharan,[10] with a tunnel to take water to Culligran power station, which is also built underground.

In addition to compensation flows, SSE maintain a schedule of freshet releases, regulated by the Scottish Environment Protection Agency, where additional water is released from Beannacharan dam into the River Farrar to simulate high-flow events which might occur naturally if the river was not impounded.

Shinwell met Tom Johnston at Pitlochry, and the two men wandered away from their advisors to have a private conversation, near the site of the future Loch Faskally.

Unlike the English and Welsh privatisation, Scottish Hydro Electric was fully integrated, remaining responsible both for power generation and for its distribution to customers.

This is an 8 MW turbine through which compensation water released from Loch Beinn a' Mheadhoin to maintain the flow in the River Affric can pass.