Green’s Dictionary of Slang

to a very great extent, very much; also as n.

1920		F.S. Fitzgerald ‘Bernice Bobs Her Hair’ in Bodley Head Scott Fitzgerald V (1963) 87: You’re an angel, and I’m obliged loads.
1935		J. O’Hara Butterfield 8 252: ‘Good luck, and I’ll see you, if not this week, perhaps a week from tomorrow.’ ‘Mm-hmm. And thanks loads’.
1954		K. Amis letter 18 Jan. in Leader (2000) 359: Thanks loads for your wire.
1961		W.R. Burnett Round the Clock at Volari’s 66: ‘I told her I thought you were a nice fellow.’ ‘Thanks loads,’ Draper said sarcastically.
1979		E. Torres After Hours 8: Thanks loads.
1985		J. Sullivan ‘Hole in One’ Only Fools and Horses [TV script] I’ve only just started. I’ve got loads more I could tell you.
2000		Indep. on Sun. Real Life 16 Jan. 3: I don’t want to go crazy and spend loads on the latest this or that.
2005		P. Howard Curious Incident of the Dog in the Nightdress 20: There’s a goy at the other end of the bor and he’s giving us loads.