twisted the cap. As the wall parted, revealing the secret apparatus, Vaughn rose and wandered over to the alcove. 'I require more data concerning the individual known as the Doctor,' he announced in a cold precise voice.
The machine fizzed and flickered before croaking its reply.
'You have sufficient information. The Doctor is an enemy and must be destroyed.'
'You state that you recognise the Doctor from Planet Sigma Gamma 14. How is that possible?' Vaughn persisted calmly.
'Your inquiry is redundant,' rasped the disembodied voice.
Vaughn's pale eyes gleamed. 'That is for me to decide.'
'You will obey.'
Vaughn stood his ground unflinchingly. 'Negative. I control the operation here on Earth. Unless that is agreed our cooperation is at an end,' he declared in a voice like cut glass.
The crystal at the heart of the machine revolved rapidly, emitting myriad points of intense light. Eventually it stopped. 'It has been agreed,' it rasped.
Vaughn smiled bleakly. 'I felt sure that your masters would be reasonable,' he purred. 'Now, how did this Doctor reach Planet Sigma Gamma 14?'
'He possesses a device.'
Vaughn's body tensed expectantly. 'What kind of device?' he demanded with suppressed excitement.
The apparatus whirred and revolved. 'No further information available. The Doctor will be eliminated. The invasion must proceed,' it decreed harshly, needles of light shooting from the crystal.
Vaughn nodded decisively. 'Oh, it will. The Doctor will be taken care of. I shall attend to it personally...'
With a vicious twist of the pen top, Vaughn banished the thing to the darkness again behind the wall.
Totally mystified, Jamie had followed the Doctor through a maze of alleys and back streets and finally up onto a railway embankment which snaked between warehouses and office blocks.
The Doctor had skipped nimbly along the sleepers and led Jamie off on a single track branch line which curved sharply round and finally brought them into a marshalling yard enclosed by high walls at the rear of the International Electromatix Building.
'This is a private branch line off the main line into Liverpool Street...' the Doctor explained, darting across the rusting rails towards a line of freight wagons bearing the familiar fist and lightning flash symbol of International Electromatix.
'But how did ye ken it was here?' Jamie panted.
'I consulted the Brigadier's excellent map,' smirked the Doctor, using the wagons as cover to approach the extensive warehouse buildings at the back of the tower. 'I memorised it to distract myself from the taste of his execrable tea.'
Following the line of wagons in the siding they soon reached a vast covered loading bay adjoining the warehouse. It was filled with stacks of cylindrical metal containers each about two and a half metres long by about a metre in diameter. Each one had a short blunt projection at both ends and a specially shaped base to facilitate vertical stacking.
Huddled against the coupling between two wagons, Jamie and the Doctor watched in amazement as a man with crew-cut hair wearing a blue boiler suit emerged from the warehouse carrying one of the containers as if it were a baby. He placed it carefully on one of the stacks and then returned to the warehouse.
'Extraordinary!' marvelled the Doctor.
'Probably empty,' Jamie whispered.
'Let's find out,' the Doctor suggested eagerly.
Leaving their hiding place, they ran over to the stack and attempted to lift the container. They failed even to budge it.
'Yon fellow must be a superman,' Jamie gasped.
The Doctor tried to raise the hinged lid, but it was securely fastened. 'I wonder what's inside?' he mused. The sound of heavy footsteps sent them scurrying behind a neighbouring stack, where they watched the same man bring an identical container and add it to the pile.
Jamie's eyes were popping with astonishment. 'Let's find the lassies and get oot,' he urged. 'That chap gives me the heebie-jeebies.'
When the man had gone,