This year, the centenary of his birth, Benjamin Britten will be inescapable. He will be celebrated with events from the publication of two major biographies to a new production of his opera Gloriana at the Royal Opera House; from a festival devoted to him in Moscow to projects as far afield as Brazil and Palestine, as well as celebrations at the festival he founded at Aldeburgh in Suffolk. The events are set to confirm his standing as the UK's most exported classical composer, and one of the most performed 20th-century composers of opera from anywhere in the world.

Britten, in life a diffident, unclubbable figure whose anguished sexuality is all too evident in his operas, is unique in the story of recent British culture. In no other artform – literature, theatre, or visual art – could it be said that one single figure dominates the horizon of 20th-century British production so forcibly. Despite never quite fitting in – when Peter Grimes was premiered in 1945, it shocked large parts of the audience with its new sounds; and by the time he died he was considered old hat by a new generation of composers whose tastes veered towards the more radical Stockhausen, Cage and Boulez – he has always loomed large. After his death he became a figure to be revered, not least by an ardent group of supporters and "keepers of the flame" – or, conversely, rejected by a new avant garde.

What is his legacy for the British cultural landscape? According to composer Colin Matthews, who was Britten's assistant in his later years, it is colossal: "He singlehandedly established opera in Britain – from a standing start." Playwright Mark Ravenhill, who is devising a project based on the composer's cabaret songs for June's Aldeburgh festival, agrees: "That old saying about England being the 'land without music' held true, at least as far as opera goes. Then, out of nowhere, you get someone writing music that could stand alongside Verdi." Matthews adds: "He also essentially created chamber opera – small-scale opera as a form. He established a format where opera could be toured and brought to the people."

The idea of bringing music to the people was key to Britten's way of being a composer. According to Jonathan Reekie, chief executive of Aldeburgh Music: "He was an absolute pioneer in music education. He was years ahead of his time, doing the sort of thing in the 1940s that people assume was invented by the Arts Council decades later." Works such as his children's drama Noye's Fludde and The Young Person's Guide to the Orchestra have shaped the early musical awareness of generations. Wes Anderson's latest film, Moonrise Kingdom, has a soundtrack dominated by such works; Britten, he has said, is "the colour of the movie".

We should not be surprised by his appeal to an American film director, suggests Janis Susskind, the managing director of Britten's publisher, Boosey & Hawkes. "He is a British composer with a global reputation – and we haven't had many of those."

Far from being a parochial figure admired only in his own country, she says, he is consistently among the top-three royalty earners of any of the composers whose estates Boosey handles – including Stravinsky, Rachmaninov, Prokofiev and Richard Strauss.

His royalties, she says, are also growing – "they went up by about 30% between 2007 and 2011". Most of the revenue comes not from the UK but the US – and she cites South America as a growth area. "Chile, Argentina, Brazil – that's a whole new frontier." The wealthy estate ploughs back money into promoting Britten. (It is a serious donor to this year's celebrations, to the tune of £300,000.) Each year it gives more than a quarter of a million to Aldeburgh Music, which mounts the Aldeburgh festival, as well as around £60,000 towards commissions for living composers.

Why is Britten so exportable? Composer Michael Berkeley thinks that it is partly the nature of the music itself. "His great gift," he says, "was clarity of thought. The music can appear a little pat, but so much of it has such economy of means: there are no extraneous notes." In short, the music is well-crafted; it works. But its very "perfection" can be off-putting to some. According to one senior figure in British music, who preferred to speak anonymously for fear of the "full might of the Britten establishment crashing down", his shadow can be "quite heavy on succeeding generations … I worry that there is a legacy from Britten's work of an approach to composition which prizes craft and technique above the strength and originality of ideas. It may be no coincidence that some of our most un-Brittenish composers have felt more comfortable pursuing their careers abroad."

It is certainly true that his sheer dominance over the British musical landscape can be burdensome to his successors. According to Matthews, "all the young composers, one after another, are called the new Benjamin Britten, until the critics and the media move on to someone else". Composer Thomas Adès has talked of the "questionable" compliment of being called "the next Benjamin Britten", which is "unhelpful and confusing". Now partly based in Los Angeles, he followed in Britten's footsteps by becoming artistic director of the Aldeburgh festival for several years, but – while praising works such as A Ceremony of Carols and the Violin Concerto – he is deeply critical of the operas, calling them "pat" and "obvious".

As time separates us from Britten's death, though, it is possible that a more relaxed attitude to the composer is emerging. For a coming generation of composers in their 20s and 30s, Britten is part of the historical furniture rather than an oedipal ancestor to be slain; and the trustees of his estate are becoming less protective, allowing more freedom in productions of his operas. There may also be room for a more realistic reappraisal of his gifts – which this year's celebrations will certainly invite. According to composer Christopher Fox: "He was very good at composing, and every so often wrote very good pieces – but he didn't move the furniture around in the way Beethoven, Cage and Stravinsky did."

The coming generation: composers on Britten

Anna Meredith, 34 I find Britten inspiring rather than daunting. I admire his clarity … He manages to make disparate elements sit together and keeps those extremes in the same world. It is very bold how stripped down his music is. The lushness is always controlled. He feels very modern in that way. He is all about limited excess: maybe that is a rather British quality.

Emily Hall, 34 I love his music. I can relate to what he was passionate about: song, theatre and choral music. The strongest thing is his melodic writing and the fact that his style is manifested through his choice of notes. You always know a melody is his – while other composers are defined by texture, or concept, or an intellectual system. I also admire the fact that when he was writing for amateurs and children it wasn't at all compromised or a struggle.

Tansy Davies, 39 For me his music can be a little sterile, too perfect – it has an oppressed quality. I like it best when the uptightness in the music is grinding up against something dark and chaotic, often an extra-musical element – that can be very exciting. That can happen in his operas, or when his work is performed by amateurs – when there is something straining against the perfection. His work in the community I find incredibly inspiring: that is absolutely what artists should be doing.