The inaugural John Peel Day opened with a charity concert at London's Queen Elizabeth Hall last night, amid a claim that he would not have approved of the event's "maudlin" and "nostalgia-driven" tone. Peel, who died in October of a heart attack, was being honoured by BBC Radio 1 for his lifetime's championship of new music.

Andy Kershaw, his friend and former Radio 1 colleague, yesterday questioned whether Peel Day was a fitting memorial. "John wouldn't have liked it," he said. "He'd think it was maudlin. He would also object on the grounds it was nostalgia-driven. He'd think we ought to spend less time doing stuff like this, and more time ploughing through stacks of records looking for the next new band." Kershaw, who now hosts a world music programme on BBC Radio 3, described the event's organisers as hypocrites who ought to have appreciated Peel more when he was alive.

Peel worked for Radio 1 from its 1967 birth. But in the months before his death at 65, he was reportedly unhappy, and upset by a decision to shift his show. "He particularly didn't like the fact he was moved so that he didn't finish work until one in the morning," said Kershaw.

When Peel died, Kershaw gave Channel 4 News an interview recounting their last conversation. "I said to him [that] he didn't look too good. And he said, 'No, I feel terrible.' He had been diagnosed diabetic a couple of years ago, and he was also finding it really hard that Radio 1 had moved him even later into the night. Marginalised is the correct word. [It] pushed him from 11pm to one o'clock in the morning and he actually said, 'It's killing me.'" Yesterday Kershaw stood by the comments. "I'm not going to go down that road again," he said. "But it's all on public record. I don't retract a word of what I said because I was merely reporting what he said to me."

Jason Carter, executive producer of live events at Radio 1 and organising Peel Day, said: "There was no suggestion from Peel's people that he was unhappy with the new time slot at all. I know the controller of Radio 1 sat down with him personally to discuss it. So far as I know he was perfectly happy about it."

The day coincides with the anniversary of Peel's final broadcast on October 13. Last night's concert offered established acts, such as New Order and Super Furry Animals, and lesser known bands like Jawbone and Venetian Snares, aiming to reflect his dual role as vital early support for some of today's biggest musicians while championing countless others who fell through the cracks. One of his most cherished bands, The Fall, also performed.

Radio 1's official celebrations kick off at 7pm this evening with six hours of live broadcasting: music from the concert, and taped tributes and live OBs from smaller gigs. At last count more than 300 Peel Day concerts were planned in the UK, the Netherlands, Germany and the US. His wife, Sheila, and son, Tom Ravenscroft, gave Radio 1 their support.

Peel was awarded an OBE in 1998, while his puppyish enthusiasm, tempered with a laconic wit, made him a mainstay of British culture for nearly 40 years. His death on October 25 last year, while on holiday in Peru left Radio 1 with a huge gap, now filled by a rotating set of three DJs. "It's significant that they've had to draft all those DJs in to replace him," said Kershaw. "But it's not the quantity of the broadcasters, it's the quality. No one is ever going to fill John Peel's shoes."