Teenagers at a secondary school in a deprived area of south Bristol will be among the first state school pupils in the West to study for the high-flying International Baccalaureate qualification from September.

The Merchants' Academy in Withywood has achieved its aim of being accepted as an IB world school, meaning it can offer the prestigious course to its students as an alternative to A-levels or vocational classes.

The International Baccalaureate involves students aged 16 to 18 studying six subjects rather than the usual three. The two-year course also involves 150 hours of community service.

The IB, which is considered a passport to higher education across the world, has been in existence for 40 years but, until recently in the UK, was taught mainly in public and international schools. The British Government is keen to see it become available in a wider social context.

Polly Higgins, the Merchants' Academy's director of post-16 studies, said: "Achieving IB world status has been one of the major goals of the academy. It is a fantastic opportunity for students in the area to access this worldwide qualification. Naturally we are absolutely delighted."

Principal Stephen Kings said: "Merchants' Academy's vision is to create an ethos of high standards and expectations. The International Baccalaureate Diploma Programme will challenge our students and allow them to have a truly global education."

The authorisation process has taken less than a year to complete and culminated in a two-day inspection by the International Baccalaureate Organisation (IBO).

The IBO commended Merchants' Academy for "the progress made in the new school, since September, in transforming expectations of students". It was also impressed by the "vision and commitment" of the community and academy to the programme.

The Red Maids' School in Westbury-on-Trym, a fee-charging girls' school, will also be offering the IB from September and St Brendan's Sixth Form College in Brislington hopes to run the IB from next year.

The first school in the area to offer the IB was The Ridings High School in Winterbourne, which began in 2006. Sidcot School, an independent Quaker boarding school near Weston-super-Mare, started its first IB students a year later.