At the beginning of this series, we said we were going to bring you through a stunning period of Irish history.

We're now at the end of that period.

September 1970, we are at the trial.

Four men stand accused of conspiring to bring hundreds of guns and thousands of rounds of ammunition into the country.

If found guilty, they could end up in jail for five years.

But it wasn't just the four men who were on trial. This young country was on trial.

Remember, it was only 50 years since the British had left,

and some of those who fought them were still in the governing party.

Kureemihin, the historian, says the arms trial of 1970, had a lot riding on it.

There was so much at stake for the political system coming out of this trial because of the various nature of the players involved.

The Gardi, the army, politicians, ministers, cabinet ministers, senior ones.

The legitimacy of the state in many ways was on trial.

And one aspect of political life that was on trial that autumn in 1970

was the fact that the political system sat uncomfortably close to the judicial system.

Most judges had been appointed by the party in government

and as we've heard, the main prosecutor, the Attorney General, was a member of that cabinet.

And while everyone swore impartiality, that uneasy closeness lobbed a grenade into the trial,

just six days in, and in fact made for a jerky start to the whole process.

Here's what happened. In the summer beforehand, they couldn't find a

judge to take the case. Too many of them had been appointed by the party that one of the accused,

former minister Charles High, belonged to. The man who eventually had to take the case, the

president of the High Court, publicly expressed his difficulties. Mr Justice O'Keeve said he'd been surprised at what he called the hysterical reaction of the newspapers.

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