Her life with her missionary parents in Burma had been full of danger and she had taken many great risks to supply the War Office in London with intelligence. She did not feel as confident as Harry and did not want to worry him. She had bought an old breastplate in an antique shop and was wearing it under her gown. She also had primed Harry’s pistol and put it in her own desk.

She heard a step on the stair and stiffened. There was something furtive about that step. The nobility who usually frequented the office would come crashing in, full of bluster, demanding that some scandal or other be hushed up or some missing dog found.

Ailsa slid open the drawer and took out the pistol, laid it on top of the desk and covered it with her scarf.

The door opened and a man in a tweed coat, knickerbockers and a flat cap came in.

‘Where’s the captain?’ he demanded.

‘Out of town. Please leave.’

He pulled out a gun and pointed it at her. ‘Go in there.’ He jerked his head at the inner office. ‘Open the safe.’

Ailsa’s hand crept towards the gun.

Finch saw the movement and shot her full in the chest. Ailsa crashed backwards in her chair and fell to the floor and lay still.

He searched in her desk until he found the keys. He went into the inner office and opened the safe. He was just reaching into it when a shot caught him on the shoulder. He grabbed his wounded shoulder and turned round. White-faced but stern, Ailsa was holding a pistol on him. He looked wildly for the gun, which he had put on Harry’s desk, but, keeping him covered, Ailsa picked it up and threw it onto the floor.

As he groaned and clutched his shoulder, she picked up the receiver and said in a crisp voice, ‘Police.’

After she had made a statement to the police and they had left with Finch, Ailsa telephoned Harry. He listened in horror and said, ‘But you said he shot you!’

‘I was wearing a breastplate,’ said Ailsa.

‘You are sharper than I am. I’ll come straight back. Meanwhile, you will find a negative and a photograph in the safe. They are in an envelope. Do not look at them. I do not want the police to see them. Please call Phil Marshall and tell him to come and pick them up. The police did not find them, did they?’

‘No, I told them he had no time to take anything.’

‘Go home, Miss Bridge. I shall go directly to Scotland Yard.’

Harry was ushered in to see Kerridge. ‘This is a bad business,’ he said. ‘The chap who tried to kill your secretary is an unsavoury character called John Finch. He says he was hired by Lord Berrow, furnished with a gun, told to kill you if necessary and to get a negative out of your safe. We sent a man back and he retrieved the negative. It was nothing but a negative and photograph of a saucy lady in the altogether. Miss Bridge said a client of yours had paid you to get the negative and photo back. She said Berrow knew of the photograph and might use it to ruin her reputation.’