rent-a-quote
/ˈrɛntəkwəʊt/originally British. Chiefly depreciative
adjective
Designating someone (especially a politician) who may be relied upon by the media to provide a comment, especially one expressing a strong or contentious opinion, either in any circumstances or when a particular issue is being discussed.
noun
A person who may be relied upon to provide such a comment.
Origin
1980s; earliest use found in The Guardian. From rent + a + quote; compare rent.