South Africa moved cautiously on to 214 for five in reply to England’s 458 at the close on the second day of the first test helped by a gritty performance from Temba Bavuma at Lord’s on Friday.
England removed captain Dean Elgar (54) and JP Duminy (15) early in the final session to take control of the match with South Africa at 104 for four but a stand of 99 between Bavuma and Theunis De Bruyn gave the touring side hope.
Broad was left unbeaten on 57 off 47 balls, including eight fours. Morkel was the pick of the South Africa bowlers with figures of 4-115.
Broad had Heino Kuhn, on debut, caught at first slip by Alastair Cook for one shortly after lunch before Elgar and Amla shared an obdurate second-wicket partnership of 72.
Elgar was dismissed soon after tea, caught off bat and pad at short leg by Gary Ballance off Moeen and Broad snared JP Duminy lbw with a full delivery which nipped back into the left-hander.
De Bruyn, in his second test, edged Anderson to wicketkeeper Jonny Bairstow for 48 just before the close but Bavuma remained on 48 not out with Rabada on nine.