The date is on the coin's obverse side, but even without that fact, the wording NEW PENCE instead of just PENCE indicates it was minted some time between 1971 and 1981, following the transition to full decimal coinage.
Assuming the coin was found in change, it's a very common circulation piece so it has no added value above 2 pence.
If the two pence coin that says NEW PENCE, and it is from 1983, then it could be worth up to £600.
The larger pre-1990 5 Pence and 5 New Pence coins were withdrawn from circulation and demonetised in 1991. So, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they have little or no value.
Anything marked "new pence" only dates back as far as 1968, and is worth face value
The "face value" of a coin is whatever is inscribed on it, hence the term "face value". The face value of a 10 Pence coin is 10 Pence.
The value of the copper in a 2 Pence coin would be significantly less then 10% of the face value of the coin at the time the coin was minted. Today, it might be a little more, about 0.2 Pence.
The first British 50 New Pence coin was issued in 1969.
The 10 New Pence coin was not introduced until 1968.
From the introduction of decimal currency in Britain until 1981, all decimal coins, except the 25 Pence coin, had the words "NEW PENCE", "NEW PENNY" or "NEW HALF PENNY" inscribed across the top of the reverse, with a numeric value at the bottom. The use of the word "NEW" was intended to assist with the distinction between old and new currency. From 1982 onwards, the "NEW" was dropped. There was a little minting accident in 1983 on the 2 Pence coin and a number of coins were struck with the word "NEW" on them.
There was no such coin in Britain. The 50 New Pence coin was introduced in 1969.
Please check your coin again and post a new, separate question. The term "new pence" was first used in 1968 when Britain began the changeover to decimal coinage.
The term "New Pence" ceased to be used on British coins in 1981. The word "Pence" should have a numeral with it to indicate how many Pence. Pence being the plural of Penny. In 1997 there would have been 50 Pence, 20 Pence, 10 Pence, 5 Pence and 2 Pence coins and a 1 Penny coin.
2 British Pence in 1979 had the equivalent value of about 1 cent USD.
The coin is called a "50 Pence" coin. The term "50 New Pence" was last used in 1981.
Such a coin does not exist. The British 50 New Pence coin was first issued in 1969. The larger pre-1998 50 Pence coins were withdrawn from circulation and demonetised in 1998. So, unless they are part of a Proof or Uncirculated mint set or are individual Proof or Uncirculated coins and in absolute mint condition, they have little or no value.
A shilling was a coin in British currency until 1971. It's value at decimalisation was 5 new pence.