WESTONBIRT School's sixth form had a private lecture from Sir Crispin Tickell, former British Ambassador to the United Nations and one of the 52 diplomats to have sent a high-profile joint letter to Tony Blair expressing disapproval of his Middle East policies.

The occasion was part of the school's sixth-form lecture programme, designed to keep the pupils up to date with current affairs.

Sir Crispin explained the role of the UN on the world stage from its inception after the Second World War through to present-day conflicts in the Middle East. He pained a vivid picture of his time as British Ambassador, bringing this important institution to life with descriptions of meetings with other Security Council members in his kitchen!

He also described his own pioneering role in drawing the world's attention to climate change. Unless the world's political leaders are prepared to commit to long-term strategies, he advised, there will be many natural disasters such as rising sea levels flooding Bangladesh and the Netherlands.

"Climate change is the biggest threat to the world - bigger than the Iraq crisis", he counselled. "The global approach required to ensure sustainability to our world must come via the UN".

He then went on to perform the official opening of the new sixth-form study centre, designed in the style of a university college library and equipped to suite the considerable demands of A-level studies. When the ceremony was over, he and his wife joined the Sixth Form prefects for dinner.

Sir Crispin donated an autographed copy of the famous letter to Tony Blair, which will be framed and displayed in the centre.