Alas, poor Declan, alack; once upon a time you seemed to be the only big name UK artist to survive the late 70s New Wave period with serious credibility (the Clash had their moments, but failed to sustain their momentum).
Costello's truly cringeworthy rendition of "Happy Birthday" to Hillary Clinton in New York last month followed closely on his appearance in a TV ad in the US for Lexus cars ( I have both to hand, but won't dignify them with the relevant YouTube links ).
Anyway, it seems that Costello has assumed the airs & graces of his namesake (Elvis, not Bud) with his ridiculously regal stance: http://www.nme.com/news/elvis-costello/32392 .
In the original Mojo interview, Costello cites his reception at the Glastonbury Festival in 2005. However, the previous February, I saw Costello at Liverpool's Royal Court Theatre, playing to a rapt & packed audience (he even jokingly dedicated "[I Don't Wanna Go To Go] Chelsea" to Steven Gerrard).
Perhaps he sees himself as the second Lennon, comfortably based in Manhattan. On this side of the Atlantic, however, his remarks evoke memories of Rod Stewart hopping across to New York with Britt Ekland.
I hope you're happy now, Elvis.