Shaw saw action at the capture of the village of Merxem in deep snow on 31 January 1814, but the weak 2/52nd was an ineffective combat unit and was left out of Graham's attack on Bergen-op-Zoom, being employed at the siege of Antwerp and subsequently on garrison duty.

They formed a battalion of marines for Dom Pedro's British-manned fleet, and Shaw was given command of the Light Company with a captain's commission.

In December 1831 they sailed to the Azores, which was Pedro's base, and after training there the ‘Liberating Army of Portugal’ landed on the mainland near Porto on 5 July 1832.

Dr Jebb, a former British Army surgeon serving with the Liberators, claimed to have operated on Shaw 12 times during the siege.

[11] After Admiral Napier's naval victory at Cape St Vincent, the Pedroites were able to use sea-lift capability to open a second front at Lisbon, and Shaw and his men later joined this force.

[12] The Miguelite army capitulated soon afterwards, and Shaw marched the British Brigade to Lisbon on 1 June where he handed over command to a Portuguese officer.

[13] In 1835 Shaw travelled to Glasgow with some of his veterans from Portugal to raise the 'Scotch Brigade' of the British Auxiliary Legion under General George de Lacy Evans for service in Spain during the First Carlist War.

[15] Shaw was made governor of Vitoria and struggled to equip the hospitals during the typhus epidemic that broke out among the BAL's unfit, cold and hungry men.

[18] He marched the brigade back to the coast in April, and embarked at Santander as part of the BAL's seaborne relief expedition to San Sebastian.

He led the centre column during the fierce action of 5 May, when the BAL broke through three lines of Carlist besiegers, and even his enemies recognised the courage he showed.

[21] On 11 July Shaw's brigade led a reconnaissance in force along the coast towards the French border, aiming to cut the Carlists off from the sea.

In 1839, during Chartist unrest in North West England, Shaw was appointed by the Government as the first Chief Commissioner of Police in Manchester and Bolton.

[32] His articles for the Caledonian Mercury[33] during the invasion scare of 1859 make his points by describing a mythical attack on the port of Leith, somewhat in the style of Chesney's later The Battle of Dorking or Swinton's The Defence of Duffer's Drift.

[34] During the siege of Oporto, a British resident described Shaw as ‘A fervid Liberal of the old Covenanter type ... fired by Dom Pedro's anti-absolutist crusades’.

[35] A British volunteer was amused by the Portuguese soldiers' long beards, but Shaw's ‘quite eclipsed all of them, being of enormous length, and as fiery in appearance as the tail of a comet’.