4.1 No Order placed by the Purchaser shall be binding on Ventis unless and until Ventis accepts the Order. Acceptance of any Order may be made by Ventis taking any steps to satisfy the Order. Any Order which has been accepted by Ventis may not be cancelled by the Purchaser except with the agreement of Ventis and, in such circumstances, only on the basis that the Purchaser shall indemnify Ventis in full against all loss (including loss of profit), costs (including the cost of all labour and materials used), damages, charges and expenses incurred by Ventis as a result of such cancellation.