England captain Michael Vaughan tosses the coin watched by South Africa captain Graeme Smith - and loses

Play starts on time with the South Africa attack looking to exploit the heavy cloud cover by generate swing and taking early wickets

Morne Morkel beats Cook's outside edge and the next over Jacques Kallis clips it only to concede four runs before England reach 50-0

Makhaya Ntini leads South African appeals for leg-before on Cook but the opener survives and helps England to 71-0 at lunch

Strauss barely put a foot wrong before the interval and he begins the middle session by defending solidly against the South African quicks

England's early dominance is confirmed as Cook reaches his 11th Test 50 and then a Strauss boundary brings up the 100 partnership

But the day swings South Africa's way when Strauss is given out lbw despite Morkel's delivery pitching outside the line of leg stump

Moments later Vaughan fails to get forward and sees his off stump clattered by a sumptuous delivery from Dale Steyn

The Proteas are on a roll and reduce England to 117-3 when Cook can only glove a rising delivery from Morkel to AB de Villers

England's South African-born all-rounder Kevin Pietersen is sent tumbling after a Steyn bouncer keeps low and rattles his helmet

But Pietersen soon finds form and gets into his stride - with South Africa's bowlers paying the penalty

And the England man is soon celebrating a half century against the country of his birth

At the other end to Pietersen, Ian Bell - after a quickfire start - settles into a more sedate rhythm

Soon it is Bell receiving congratulations from Pietersen for his own 50 as England recover strongly from their mini-collapse

England's recovery continues - and it is Kevin Pietersen celebrating his 13th Test century

South Africa captain Graeme Smith is left with plenty to ponder at the end of the first day's play at Lord's

But the day belongs to England's Kevin Pietersen who resumes on Friday on 104 not out