The first gap was the Darien Gap between Colombia and Panama, the second was the Bering Strait between the United States and Russia, and the third was the Channel Tunnel between France and Britain.

Because of the rules of his assignment, Karl is unable to use any form of transportation and must return home on foot.

Karl has been arrested in Panama for crossing a forbidden border zone, so it’s not unusual for him to be in trouble.

After successfully overcoming the first two gaps, even hotter water may follow in the form of his 25-year journey being wasted if he is unable to reach the English Channel.

While the Brit is capable of swimming, it is unlikely that he will be able to do so in these chilly and shifting conditions.

That left him with just one option: use the Channel Tunnel rather than the trains, which run all day and night.

Between the regular train operations sections, there is a short extra tunnel designed for maintenance workers.

According to Getlink Group, this service tunnel has a diameter of 4.8m and “lies between the two rail tunnels 15m apart.”

The tunnel is an excellent alternative for Karl because it is utilized to provide access to maintenance and emergency rescue personnel in the event that people need to be evacuated.

The only issue is that he must have the proper authorization in order to stroll through it, as foot passengers are typically prohibited.

As per Armchair Adventure Festival, Karl said: “Would they say no after decades of effort and only 21 miles from home?”

If all goes smoothly, the ex-paratrooper will be home in no time and able to rest his ailing feet.

Then again, it took Karl 11 years to conquer half of Russia due to multiple visa complications and a five-year restriction on re-entering, so who knows what awaits him now.

You may see the most recent updates on Karl’s Goliath Expedition here.