The Home Office has criticised Channel 4 as “insensitive and irresponsible” after the broadcaster said a programme in which contestants attempt to “smuggle” themselves into the UK would go ahead less than a fortnight after the Essex migrant tragedy.

The screening of the first episode of Smuggled, a two-part series billed by Channel 4 as “the largest test of our borders ever conducted by the media”, was postponed last week after the bodies of 39 people were found inside a lorry container on an industrial estate in Grays.

But after Channel 4 said it would be delayed by only one week, the Home Office hit out at the broadcaster, saying: “Broadcasting this programme so soon after the tragic incident at Grays is both insensitive and irresponsible.

“Organised crime gangs have no respect for human life so it is reckless to provide a platform for the illegal activity that they facilitate. Doing so simply encourages them to exploit our border for profit, risking the lives of vulnerable, desperate people as they do so.”

Channel 4 insisted the decision was correct under its public service remit because “more than ever, following this awful tragedy, the shocking findings of the films have become a matter of urgent public interest”.

When the programme airs on Monday after what were described as production amendments designed to alter its tone and take account of the tragedy, viewers will watch as the first four participants successfully enter Britain by clandestine means.

They consist of a man who hides in the back of a truck cabin, a grandmother who conceals herself inside a mobile home van, a watersports instructor who crosses the Channel from France in a motorised inflatable and a journalist who enters on a ferry from the Netherlands using someone else’s passport.

All four were filmed either not encountering any border checks on their route from the continent or managing to gain access to Britain without being stopped.

David Modell, the executive producer of the series, told the Guardian he and others had reflected intensively on events after news of the Essex tragedy emerged but said the programme was never going to be pulled indefinitely.

“Subtle” changes were made to the tone of the programme, which now carries a statement at the beginning saying it was made before the events in Essex, he added, and there was a belief that it should now be broadcast as soon as possible.

“It was absolutely a collective decisions and one that everybody felt very comfortable with,” he added. “We all felt we want it to go out with in proximity to the tragedy because it does something helpful.”

Model added that the programme-makers had set out not to be judgmental about people who attempt to enter the UK and pointed out that it includes a section referring to polls finding that the British public overestimates the number of people claiming asylum in the UK. Participants in the programme, including a young man who was born in Sierra Leone, are also showed passionately arguing why desperate refugees and migrants attempt to reach Britain in search of a new life.

Those involved expressed shock when they were able to reach Britain, whether it was landing on a beach in Dorset or passing through ferry port passport controls.

“None of us, when we set out to make this series, thought that we would get more than a couple of routes through to be honest,” said Modell.

“None of us expected to have the kind of success rate and what it revealed to us was that that if you have got a bit of resources or a bit of planning you can get pretty much anybody or anything into the country. We found along the way that the attention has been focused on lorry jumpers, the poorest people who are trying to get on lorries.”