Shell came under fire at its annual meeting yesterday from environmental campaigners who accused it of peddling "shameful, absurd and misleading" adverts about its green credentials and of presiding over a growing number of oil spills and defying court orders to halt gas flaring in Nigeria.

The Dutch arm of Friends of the Earth (FoE) said that Shell had taken out a series of adverts that presented the company as a leader in renewable energy and one that was tackling carbon output from refineries by using it to grow flowers in nurseries.

Yet less than 1% of Shell's schemes related to renewable power whereas "99% are not sustainable" because they are related to oil and gas, said Paul de Clerck, a representative from FoE. There was only one scheme in which greenhouses were heated by a refinery, he added. The FoE filed a complaint to the Advertising Standards Authority yesterday.

Rob Routs, a board member with responsibility for oil products and chemicals, denied that Shell was deliberately misleading anyone and insisted the adverts were just a message to its staff and others of its intent to help with the environment. "It's a way we get interest in our projects," he said. "Are we going to stop them? No."

A procession of environmentalists and other shareholders attacked Shell over its record in Nigeria, where Shell has repeatedly appealed judgments on flaring, saying it will deal with the issue by 2009.

Malcolm Brinded, Shell's head of exploration and production, said $3bn (£1.5bn) had been spent on anti-flaring projects over the past six years. But lawlessness in the area, difficulties with government funding and other problems complicated its work, he added.

Basil Omiyi, Shell's managing director in Nigeria, even questioned the 2009 deadline in the company's sustainability report. "We believe this can still be achieved, provided we get access in time and the needed funding. I am afraid I cannot be any more definite," he said.