18.    Share-based payments

The Group has share option schemes for employees of the Group. Options are exercisable at the price agreed at the time of the issue of the share option. The vesting periods are consistent between employees. Options are typically forfeited if the employee leaves the Group before the options vest. Details of the share options granted during the period are as follows:

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18.    Share-based payments (continued)

The options outstanding at 30 September 2021 had a weighted average exercise price of £0.0001 ($0.0001) pence, and a weighted average remaining contractual life of 4 years. Share options were issued within Arqit Limited, and therefore the share price and exercise price have been stated in pound sterling due to this being the currency which the instrument relates to. Volatility is based on management’s best estimate given that no historical share price is available. The inputs into the Black-Scholes model are as follows:

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