(ShareCast News) - Tesco's new chairman John Allan bought 51,978 shares in the supermarket giant on Tuesday.Allan, who took over from Sir Richard Broadbent in March, purchased the shares at 192.39p each, amounting to a total value of £100,000.The chairman also spent a further £186,000 on buying up Tesco bonds. He bought 198,000 medium term notes offering 5.5% annual interest which mature in 2033 for 94.08p each.