The Serious Fraud Office has launched an investigation into French defence giant Thales for suspected bribery and corruption.

Authorities in the UK and France said they are carrying out a joint probe into the firm, which employs more than 7,000 staff in the UK.

Thales is one of the Government’s key defence contractors, and built hundreds of lightweight missiles which the UK sent to Ukraine in September.

It comes after police in France, the Netherlands and Spain searched the company’s offices in June, over suspicions of corruption linked to arms sales abroad, according to reports.

Investigators from the SFO and French authority Parquet National Financier have informed the company of the investigation, they said on Thursday.

Thales confirms that the SFO and the PNF have commenced an investigation in relation to four of its entities in France and the UK

Director of the Serious Fraud Office, Nick Ephgrave QPM, said: “Working collaboratively with our international partners is a crucial factor in the fight against international corruption and with this case I hope to reinforce the SFO and PNF’s long-standing relationship, built on mutual cooperation and shared success.

“We will together rigorously pursue every avenue in our investigation into these serious allegations.”

Thales specialises in defence electronics, and built the 650 so-called Lightweight Multirole Missiles (LMMs) that the UK announced it would supply to Ukraine in September, in a £162 million order.

The lightweight weapons, manufactured at one of Thales’ plants in Belfast, are designed for short-range fire, and can hit targets up to about six kilometres away in the air and on the ground.

Thales also won a £1.8 billion UK defence contract in February, which will see it maintain the Royal Navy’s fleet of ships and submarines for the next 15 years.

A Thales spokesperson said: “Thales confirms that the SFO and the PNF have commenced an investigation in relation to four of its entities in France and the UK.

“Thales is co-operating with the PNF in France and the SFO in the UK. The group complies with all national and international regulations.

“As the investigation is ongoing, Thales will not comment further.”