If you give away £250,000 to your daughter, you will have made a "potentially exempt transfer" to her. What that means is that so long as you live for seven years after making the gift, it will not be included in the valuation of your estate for Inheritance Tax purposes when you die. If you die within seven years of making the gift, its value will be included in your estate for IHT purposes.
The first £325,000 of your estate will be exempt from IHT when you die and if that estate includes gifts made in the seven years before you die, the £325,000 exemption will be used first against those gifts in chronological order. Take a look here
for information on Inheritance Tax and here
for information on who pays it. In particular you should read the section headed "When a beneficiary or a 'donee' has to pay Inheritance Tax". You might also read about transfering a nil-rate Inheritance Tax band here
If the passing of your parents was within the last two years, you might consider a Deed of Family Arrangement" whereby you can renounce your inheritance in favour of your daughter. This would avoid any potential IHT liability for your estate on the £250,000 you would otherwise receive. You should discuss that with the solicitor dealing with the estates to make sure that such an arrangement would not cause other problems tax wise for the estates of your late parents. You can read about Deeds of Family Arrangement here
You might consider contacting the people here
to make sure that your inheritance will not affect your husband's pension credit entitlement. It won't affect your state pension.
I hope this helps but let me know if you have any further questions.