Babcock International Group plc is a British[5] aerospace, defence and nuclear engineering services company based in London, England.

Although the company has civil contracts, its main business is with public bodies, particularly the United Kingdom's Ministry of Defence and Network Rail.

[6] During the 1870s and 1880s, the company, having decided to expand internationally, developed an initial footprint in the British market, centring on cities such as Glasgow, Scotland.

[7] Following its establishment, the British company's sphere of operation was defined as 'the world except for North America and Cuba', which was the preserve of the US Babcock & Wilcox venture.

[9] During 1895, Babcock & Wilcox Ltd opened a new boilermaking works, based on the 33-acre (130,000 m2) site of the Porterfield Forge on the opposite side of the River Clyde near Renfrew.

[5] Shortly thereafter, the newly merged company's head office in London and more than two-dozen plants were closed, causing the loss of around 6,000 jobs, over half of these based in Britain, reducing its workforce to less than 30,000.

Reflecting the successful shift in the company's strategic focus, in 2002 Babcock was duly reclassified on the London Stock Exchange from 'Engineering' to 'Support Services'.

[12] On 9 May 2006, it went on to acquire Alstec Group Ltd, a nuclear and airport services operator,[16] and on 13 June 2006, it bought the high voltage power lines and mobile telecoms business of ABB South Africa (Pty).

[18] On 7 August 2007, acceptances for the acquisition of International Nuclear Solutions PLC reached 58.9% of issued share capital, and a takeover was then completed.

The acquisition, which was completed on 8 July 2010, created a combined defence and support services group that annually accrued sales of £3bn and had more than 25,000 employees, which were mainly based in Britain and the United States.

[31] In August 2014, Babcock issued a statement declaring that there would be job losses at HMNB Clyde if Scotland were to vote in favour of independence in the 2014 Referendum.

[32] In October 2014, both Babcock and BAE Systems won contracts from the Ministry of Defence worth a total of £3.2 billion to maintain British warships, submarines and naval bases for the following five years.

[37][38] Reportedly, Rupert Soames, Serco's Chief Executive, remained interested in aligning his company's defence operations with Babcock's own divisions.

[41] The firm's decision to downsize its S-92 inventory caused manufacturer Sikorsky to sue Babcock over its refusal to accept delivery of units ordered in 2011.

[45] In February 2023, the British Royal Navy ordered an investigation into the repairs made by Babcock International engineers on a Trident submarine after it was discovered that glue had been used to fix broken bolts in the nuclear reactor.