Valiant Petroleum plc

20 May 2010

PRESS RELEASE

Commencement of Don Phase II Development

Valiant Petroleum plc ("Valiant" or the "Company") is pleased to announce that the John Shaw semi-submersible rig has now arrived on location and has begun drilling operations on the Don Southwest (Valiant, 40.0%) as part of the second phase of field development.

The second phase of development on Don Southwest is focused on targeting reserves in the 'Horst' compartment in the north of the field located between Areas 5 and 6. The 'Horst' was discovered during the 2009 drilling campaign and contains some of the best reservoir quality found to date in the field. The development includes a production well, which will be drilled first, followed by a water injection well to deliver pressure support into the compartment.

Drilling on the 'Horst' compartment of Don Southwest is anticipated to be completed during the third quarter following which the rig will be used to drill an appraisal well into the 'H' compartment of Don Southwest, also discovered during 2010, and potentially a third production well on West Don, subject to final partner agreement.

Following a period of sustained production in-line with expectations from the Don Southwest and West Don (Valiant, 17.275%) fields following commissioning of the Thistle export route in March, Valiant is also pleased to reiterate its current production guidance for 2010 of 6,500 to 7,500 barrels of oil per day.

Peter Buchanan, CEO, commented:

"The second phase of the Don fields development has begun on schedule and we look forward to working with our partners to realise the full potential in and around the Don fields. Continued strong production from the combined fields gives us further confidence in the ultimate deliverability from the reservoirs in the area.

In addition to the drilling programme on the Don fields, the next few months is set to be an exciting period for Valiant with further drilling results anticipated from the Tybalt exploration well and the spud of the high-impact Viola exploration well."

In accordance with the AIM Rules, the information in this announcement has been reviewed and signed off by Brian Elliot, Operations Director, who has over 20 years relevant experience within the sector.

ENDS