Two corrupt businessmen, including a former CEO from Ellesmere Port, who bribed government officials in Iraq and Indonesia to win lucrative contracts for one of the world's biggest chemical companies have been jailed for a total of six years.

Former Innospec CEOs Paul Jennings, 57, of Willaston and Dennis Kerrison, 69, of Surrey, plotted to pay a series of backhanders to secure business for their toxic lead fuel.

Jennings and his business director Dr David Turner, 59, of Newmarket paid off officials during the demise of the Saddam Hussein regime so tests on unleaded fuel manufactured by a rival company would come back unfavourably.

Innospec eventually illegally profited £403m through involvement in the Iraqi Oil for Food programme and bribery of officials from the Gulf nation.

Jennings, Kerrison, Turner and scientist Dr Miltiades ‘Miltos’ Papachristos, 51, also oversaw millions of pounds in kickbacks being handed to public officials from the Indonesian government.

At least £8.5m in bungs were paid to agents so that the southeast Asian nation would not switch to unleaded fuel and continue to use Innospec’s toxic tetraethyl lead in petrol engine cars.

Most vehicles now use unleaded fuel due to concerns over TEL and its effects on the environment.

But Jennings, Turner, Papachristos and Kerrison tried to ensure Innospec’s continuing sales of TEL in Indonesia by delaying its introduction of unleaded fuel - achieved through the wholesale bribery of its officials.

Andrew Mitchell QC, prosecuting at Southwark Crown Court, said: “In order to conduct business abroad companies appoint agents to perform lawful business in other countries. Innospec appointed agents to undertake and perform lawful services.

“However, in Indonesia and Iraq it is clear that Innospec employed corrupting practises to promote the declining TEL business.

“What lies at the heart of this case is that, in the face of worldwide environmental and health pressure to change to unleaded fuel, the company accepts that its bribes, offered to state officials in return for favouring TEL, meant that its continued life was extended beyond what it might otherwise have been."

Innospec, formerly known as Octel and based in Delaware in the US, employs around 800 people worldwide, with half of those at its UK plants in Widnes and Ellesmere Port.

Innospec was fined £28m in March 2010 as part of a joint investigation between the Serious Fraud Office and the US Department of Justice in the United States.

Jennings, Turner, Kerrison, and Papachristos were later charged with conspiracy to corrupt.

“Corruption has been described as an insidious plague that has a wide range of corrosive effects on societies,” Judge Andrew Goymer said.

“Although leaded petrol is being phased out and is doomed to extinction, it is, however, profitable for a monopoly manufacturer.”

Jailing Jennings for two years, Kerrison for four years, and Papachristos for 18 months, Judge Goymer added: “Corruption at Innospec was ingrained and endemic - it was institutionalised.”

Turner, who gave evidence against Kerrison and Papachristos during their three-month trial, was handed a 16-month prison sentence suspended for two years and 300 hours unpaid work as a result of his cooperation.

Jennings and Turner both admitted three counts of conspiracy to corrupt.

Kerrison and Papachristos, of Thessaloniki, Greece, were both found guilty of conspiracy to corrupt.