Apparently, Roger suspected Lloyd-Webber of stealing some of "Echoes" in the writing of "Phantom Of The Opera". Here is a more detailed explanation:
"What's the deal with Andrew Lloyd Webber?"
In general, (Roger) just doesn't like ALW's music, and doesn't mind saying so. But specifically, there's a section of Webber's _Phantom of the Opera_ that bears a marked similarity to a part of ``Echoes.'' The opening notes to the ``Overture'' of _Phantom_ (Track 2, Disc 1) are C# C B Bb A C#. This matches rather closely a section of ``Echoes,'' approximately 6:06 to 6:16. While Waters was less than pleased with this similarity, Echoesians have pointed out that such a chromatic pattern is fairly common; by no means a Floyd invention. However, the relevant dates make the charge of plagiarism at least possible, if not really likely -- Webber first used the riff in question on the film ``Gumshoe,'' released in December 1971. _Meddle_ was released on 11 November, 1971, with the live debut of ``Echoes'' having occurred on April 22.
In an interview about ATD, waters said the following:
"Andrew Lloyd Webber sickens me. He's in your face all the time and what he does is nonsense. It has no value. It is shallow, derivative rubbish, all of it, and it makes me very gloomy.[

(stratman)]. Actually, I've never been to one of his shows but having put that slightly savage joke on the record,(There's a lyric on Amused To Death which runs thus: "Lloyd Webber's awful stuff/Runs for years and years/An earthquake hits the theatre/But the operetta lingers/Then the piano lid comes down/And breaks his ****ing fingers.") I thought I'd better listen to some Andrew Lloyd Webber and I was staying in a rented house in America this summer and the people who owned the house had a whole bunch of his rubbish so I thought I'd listen to Phantom Of The Opera and I put the record on and I was slightly apprehensive. I thought, Christ, I hope this isn't good - or even mediocre. I was not disappointed. Phantom Of The Opera is absolutely ****ing horrible from start to finish."