At Paragon Clampin was director of mortgage underwriting, while he also spent 18 years at Mortgage Trust in a career spanning 29 years.
Clampin said: “There is a lot of excitement building in the buy-to-let lending industry around Landbay and I’m certainly looking forward to playing my part in helping the business to grow.
“The Landbay model is built on the very compelling combination of an innovative technology platform with experienced and high quality underwriting.
“I’m looking forward to building on what is already in place to help Landbay meet its exciting growth targets.”
Clampin is the latest major appointment at Landbay, as Robert Burgess joined as non-executive director in February and Julian Cork joined as chief operating officer in March.
Landbay launched with the plan of achieving a £1bn loan book by 2018, but it is now targetting achieving £1bn of lending per annum by 2018.
John Goodall, co-founder and chief executive of Landbay, said: “Attracting people of Paul’s calibre is a testament to the strong foundations we have put in place for Landbay and means this business is ready to enter a new phase in its growth.
“Our lending volumes are set to increase substantially over the next 18 months, and I’m sure Paul will do a fantastic job of scaling up our lending capacity, while maintaining the high underwriting standards that form the bedrock of our model.
“The first half of 2015 has seen our senior team grow with a host of exciting names, and we know Paul’s contributions will take us to new heights.”