This is the first time that net lending has dipped into minus figures since the BBA first started compiling its figures in September 1997.
Even when the credit crunch first hit in 2008 and 2009, net mortgage lending each month fluctuated each month between £5bn and £2bn.
But in June 2011 it sunk below the £1bn mark and since then it’s varied on a monthly basis between £300m and £900m.
Last month in April net mortgage lending was £516m before dropping to -73m in May.
Overall gross mortgage lending of £7.9bn in May was below the six month average as the housing market continued to see subdued activity.
The BBA says: “Historically, the difference between gross lending and capital repayment produced significant increases in net lending each month.
“With a stable level of gross lending, but a rising trend in capital repayment, reflecting low interest rates, the difference has gradually narrowed to the point in May where repayment exceeded lending.”