QATAR wants to help Iran to develop its share of the world’s biggest gas field so both countries can reap the maximum long-term rewards, sources at state-run Qatar Petroleum (QP) say.

The Gulf state has offered its support in response to a request from Iran amid signs that western sanctions might ease after it signed a deal in November that offers more transparency over its nuclear programme.

The giant gas field beneath the waters of the Gulf, which Iran calls South Pars and Doha calls the North Field, accounts for nearly all of Qatar’s gas production and around 60 per cent of its export revenues.

Multi-billion dollar plants built with big Western energy companies have helped Qatar become the world’s largest liquefied natural gas (LNG) exporter, while western sanctions have prevented Iran from mirroring that success. Worried that overproduction might reduce long term recovery from its biggest asset, in 2005 Doha imposed a moratorium on new developments.