The second-half was another tight affair. It looked like the Irish would get in out wide but Jones intercepted at the crucial moment.
Kerr grabbed the first points after the restart with a well-taken penalty, while Murphy pushed an effort of his own wide.
The end-to-end scoring would soon dry up as both sets of players became edgy in the Cape Town heat. Ireland pushed for some much-needed territory but handling errors at crucial moments, both in attack and defence, handed England the impetus.
Kerr sent a penalty against the posts, but made no mistake with another effort that put eight points between the sides after another scrum penalty.
He would have the final say as he kicked his fourth penalty with the final act to spark wild celebrations, having held Ireland scoreless in the second half.
England: Ioan Jones; Ben Redshaw; Ben Waghorn, Sean Kerr; Alex Wills; Ben Coen, Ollie Allan; Asher Opoku-Fordjour, Craig Wright, Afolabi Fasogbon; Joe Bailey, Junior Kpoku; Finn Carnduff (capt), Henry Pollock, Nathan Michelow.
Replacements: James Isaacs, Cameron Miell, James Halliwell, Olamide Sodeke, Kane James, Lucas Friday, Josh Bellamy, Toby Cousins.
Ireland: Ben O’Connor; Finn Treacy; Wilhelm de Klerk, Hugh Gavin; Hugo McLaughlin; Jack Murphy, Oliver Coffey; Ben Howard, Danny Sheahan, Jacob Boyd; Alan Spicer, James McKillop; Sean Edogbo, Bryn Ward, Brian Gleeson (capt).
Replacements: Stephen Smyth, Emmet Calvey, Patreece Bell, Billy Corrigan, Luke Murphy, Tadhg Brophy, Sean Naughton, Sam Berman.
