Just have a look at https://en.wikipedia.org/wiki/List_of_museums_with_Egyptian_... to get an rough idea of the extent of Egypt-mania in Britain; the 'UK' section dwarfs the others! So although that quote is rather vague, I strongly suspect that it is simply referring to the large quantity of Egyptian artefacts that were being excavated and moved to museums in Britain, especially after Epypt was annexed by and amalgamated into the British Empire in 1882.