| Year ended 31 July 2022 | Note |  2022  LKR  | 
       2021  LKR  | 
    
| Cash flows from/(used in) operating activities | |||
| Surplus/(deficit) before tax | 912,490,870 | 132,311,090 | |
| Adjustments for | |||
| Depreciation of property, plant and equipment | 3.2 | 73,591,864 | 83,180,603 | 
| Amortisation of intangible assets | 5 | 264,894 | 1,986,917 | 
| Amortisation of leasehold rights | 4 | 634,941 | 634,941 | 
| Profit/(Loss) on disposal of fixed assets | 17 | (1,937,587) | (2,386,547) | 
| Income from investments | 15 | (47,569,837) | (51,785,983) | 
| Provision for post-employment benefit plan | 9 | 136,555,288 | 106,408,517 | 
| Provision for bad and doubtful debtors | 14 | – | 1,116,855 | 
| Payable written back | 15 | – | (4,935,415) | 
| Operating profits before working capital changes | 1,074,030,433 | 266,530,978 | |
| Changes in working capital | |||
| Decreased/(increased) in receivables and prepayments | (282,123,872) | (57,627,702) | |
| (Decreased)/increased other payables | (5,440,863) | 127,894,160 | |
| Cash generated from operating activities | 786,465,698 | 336,797,437 | |
| Post-employment benefit plan paid | 9.1 | (187,503,109) | (81,405,581) | 
| Interest received | 47,569,837 | 51,785,979 | |
| Economic Service Charge (ESC) written-off | 17.4 | 17,571,324 | – | 
| Net cash generated from operating activities | 664,103,750 | 307,177,835 | |
| Cash flows from/(used in) investing activities | |||
| Acquisition of property, plant and equipment | 3.1 | (61,206,689) | (46,658,963) | 
| Addition of assets under construction | 3.1 | (808,713) | (1,909,637) | 
| Proceeds from disposal of property, plant equipment | 3,170,747 | 3,880,205 | |
| Investment recovered/(made) | (55,282,572) | 68,725,016 | |
| Net cash from/(used in) investing activities | (114,127,227) | 24,036,621 | |
| Cash flows from financing activities | |||
| Net receipts on school projects | (1,286,501) | 26,346 | |
| Net cash from in financing activities | (1,286,501) | 26,346 | |
| Increase/(decrease) in cash and cash equivalents | 548,690,022 | 331,240,802 | |
| Cash and cash equivalents at the beginning of the year | 8 | 570,139,611 | 238,898,809 | 
| Cash and cash equivalents at the end of the year | 8 | 1,118,829,633 | 570,139,611 |