Speaking to Today's Nick Robinson, the prime minister said "Brexit has caused more harm than good", and the government is exploring "different options".
He also agreed that the UK is facing an energy crisis but refused to say whether people will be offered more than the temporary VAT cut to help with rising energy bills.
When pressed on his vow to scrap the state pension triple lock by 2030, he said it will be an "adjustment" that keeps "in play" the three elements of rising with inflation, 2.5% or reflecting earnings growth.
