in a dig at the prime minister , the ukip leader said that he was ` jealous ' of how the tory leader has reversed the greying process while in downing street .
after clashing at last week 's televised leaders debate , mr farage said he had shaken mr cameron 's hand and ` complimented him on his appearance ' .
mr cameron , 48 , has previously been accused of visiting stylists and even trichologists to keep his hair looking youthful .