Me and my family, my wife my son aged 11 and daughter aged 9 travelled via Germany from UK to Tunisia for a 8 night holiday. We all hold UK passport therefore no visa is required. Hotel and transfer and return flight had been booked. On arriving at Tunis we as a family were denied entry with no reason other then the way we looked. We were forced to spend night in cramped and uncomfortable chairs. Then escorted on to return flight and then once on airplane passport were return with boarding card. We returned to UK via Germany 32 hours after leaving UK. Travel insurance will not pay any cost as there is no insurance for this situation. Can any one suggest if there is any way I can reclaim any cost.Thanks.
I assume you ask whether you can recover from the government of the country which refused you entry.
Generally you cannot recover those costs. The only exception is if you arrived in a country you have a right to admission to (which usually means you are the citizen of this country), and were illegally refused admission.
The reason for this is that you have no legal or contractual "right to admission" into a foreign country. Obtaining a visa does not equal to a contract giving you admission privileges - it only allows you to travel to the point of entry where the immigration would make a final decision whether allow or deny your entry. You might be able to challenge this decision (sometimes only in form of appeal to an immigration supervisor at spot), but once you departed back, it is forfeited.
In my opinion the above stays true even if you were denied entry for the unlawful reasons, such as because immigration officer did not like your race or religion. And proving this would be difficult, because the officer must record the denial in their system using one of the authorized codes. Still you can then challenge this decision at your expense in a Tunisian court, but even if you win, this would likely only result in invitation to "visit again" (still without a guaranteed entry) and a penalty to the officer - rarely worth the effort.
If you booked a package through an ABTA accredited travel company, you might be able to recover something, typically ABTA covers you against a lot of things that travel insurance doesn't. You may not receive a full refund but a sympathetic travel company might be able to give you another holiday of roughly equivalent value or refund you the cost of everything but the flights. These companies also want to keep good PR, so it's worth calling them up and explaining what happened.
If your ordeal is particularly noteworthy you might be able to hawk it to the press as a pity or outrage story for some compensation. It might seem seedy but it is an option.
No travel insurance company I know of will cover costs due to denial at port, even the most expensive policies, so you're SOL there.
Honestly, if you genuinely believe that you were denied because of your looks (I'm going to guess you look Middle Eastern), I would not risk travelling anywhere like North Africa (or possibly even the US) for the foreseeable future unless absolutely necessary. If you really want to play it safe stay in the EU, you cannot be denied entry except under exceptional circumstances with a British passport under freedom of movement (at least until we leave, but that's still some way off). It's not fair, but that's unfortunately the way it is right now.