LONDON (AP) — Complex and inflexible U.K. visa rules are deterring international artists from coming to Britain and robbing U.K. audiences of the chance to see global talent, leaders of several major arts festivals said Wednesday.

This summer the WOMAD world music festival and the Edinburgh International Book Festival have both complained that several invited performers have been denied visas. Last month, WOMAD founder Peter Gabriel said Britain risked becoming "a white-breaded Brexited flatland ... losing the will to welcome the world."

In a letter to the Guardian newspaper, directors of events including WOMAD, the Hay group of literary festivals, Celtic Connections and the Manchester International Festival said the "lengthy, opaque and costly" visa application process was deterring artists from visiting Britain.

They urged the government to make the process cheaper and more flexible, saying "these refusals directly reduce U.K. audiences' opportunities to see and engage with international artists."

Many of those who have had problems are from Africa and the Middle East. Britain's exit from the European Union will also end the automatic right of people from 27 EU nations to come to Britain — and it's not certain what, if any, visas European artists will need to perform in the U.K.

In a speech Wednesday at the Edinburgh Television Festival, Culture Secretary Jeremy Wright said the government "understands how important mobility is" for the creative sector and intends to seek a post-Brexit culture accord with the EU.

In advance extracts released by his office, Wright said the proposals include "reciprocal arrangements to allow U.K. nationals to visit the EU without a visa for short-term business reasons" and vice-versa.