7(1)Where the responsible partners are liable—
(a)to make a payment of tax or to interest on unpaid tax,
(b)to make a payment in accordance with an assessment under paragraph 29 of Schedule 10 (recovery of excessive repayment), or
(c)to a penalty under this Part of this Act or to interest on such a penalty,
the liability is a joint and several liability of those partners.
(2)No amount may be recovered by virtue of sub-paragraph (1)(c) from a person who did not become a responsible partner until after the relevant time.
(3)The relevant time for this purpose is—
(a)in relation to so much of a penalty as is payable in respect of any day, or to interest on so much of a penalty as is so payable, the beginning of that day;
(b)in relation to any other penalty, or interest on such a penalty, the time when the act or omission occurred that caused the penalty to become payable.