How do I retrieve json based errors instead of standard .net

I am hitting a web services that returns its errors as a json. How can I interpret these errors when I am using a web client? I want to be able to pass these onto my users so they no the errors they are getting.

{ "success": false, "errors": [

{

"propertyName": "Reference",

"reason": "'Reference' must not be empty."

},

{

"propertyName": "Reference",

"reason": "'Reference' should not be empty."

},
{
"propertyName": "Key",

"reason": "'Key' must be between 10 and 15 characters. You entered 3 characters."

},
{
"propertyName": "Key",

"reason": "Key does not start with zero: 123."
} ], "warnings": [], "information": []

This is how I am calling out to the third party api but when I hit this line I'm getting a standard .net error throw back my question is how can I instead get the values of the above json back

var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();

Screen shot as i cannot upload

https://snag.gy/Itoy02.jpg

public void TransferToSlate(string json, string url)

{

        var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);

        httpWebRequest.ContentType = "application/json";

        httpWebRequest.Method = "POST";



        using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))

        {

            streamWriter.Write(json);

        }



        var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();

        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))

        {

            var result = streamReader.ReadToEnd();

        }

}

Edit 2
I have tried the following and its got me a bit futher but not to the desps of the two list propertyes within errors

public void TransferToSlate(string json, string url)

 {



  try {

         var httpWebRequest = (HttpWebRequest)WebRequest.Create(url);

            httpWebRequest.ContentType = "application/json";

            httpWebRequest.Method = "POST";



            using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))

            {

                streamWriter.Write(json);

            }





            var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();

            using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))

            {

                var result = streamReader.ReadToEnd();

            }

        }

        catch (WebException ex){



            var resp = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();



            dynamic obj = JsonConvert.DeserializeObject(resp);

            var messageFromServer = obj.error.message;



        }

So I created this class but im not to sure how to deserilize errors to it

 public class ErrorMessage

 {

    public string PropertyName { get; set; }



    public string Reason { get; set; }



    public override string ToString()

    {

        return string.IsNullOrWhiteSpace(PropertyName) 

            ? Reason 

            : string.Format("{0} : {1}", PropertyName, Reason);

    }

}