Child that I am, I couldn’t resist looking up to see which Lord has used the most “f” words. It turns out that just one Lord has used this expletive in the Lords: one Lord Philips of Sudbury.
Anyone who has ever heard Lord Philips speak outside of the Other Place will be unsurprised by this revelation. He spoke at the launch meeting of NO2ID a couple of years ago and engaged in a tirade of sweary words. Enormous fun was had by all.